How to Enforce a Patent in Denmark: Step‑by‑step Procedure, Injunctions, Timelines and Costs

Last reviewed: June 22, 2026

Understanding how to enforce a patent in Denmark is critical for any rights‑holder that discovers unauthorised use of its technology in the Danish market. Denmark offers a well‑developed enforcement framework centred on the Maritime and Commercial Court (Sø‑ og Handelsretten), with remedies ranging from preliminary injunctions and permanent injunctive relief to damages, seizure of infringing goods and customs border measures. In early 2026 the Danish Supreme Court refined the standard courts apply when assessing patent validity at the preliminary‑injunction stage, a development that materially affects the tactical calculus for every patent owner weighing urgent relief against main proceedings.

This guide consolidates the entire patent infringement procedure Denmark practitioners follow into a single procedural roadmap: eligibility checks, step‑by‑step filing instructions, an evidence checklist, realistic enforcement timelines, indicative costs and the 2026 case‑law changes that shape current practice.

Overview of the Enforcement Process and Who It Applies To

Patent enforcement in Denmark is governed primarily by the Danish Patent Act (Patentloven) and the general rules of civil procedure in the Administration of Justice Act (Retsplejeloven). The process applies to holders of Danish national patents, European patents validated in Denmark, and, since Denmark ratified the Unified Patent Court Agreement, Unitary Patents where the rights‑holder elects to enforce nationally rather than (or in parallel with) the UPC.

First‑instance patent infringement claims are typically heard by the Maritime and Commercial Court in Copenhagen, which has specialist technical judges. Appeals lie to the High Court (Østre Landsret or Vestre Landsret) and, with leave, to the Supreme Court (Højesteret). The Danish Patent and Trademark Office (DKPTO) handles administrative proceedings, oppositions, limitations and revocations, but does not adjudicate infringement.

Key Remedies Available

• Preliminary injunction. Urgent interim relief prohibiting the alleged infringer from continuing infringing acts pending trial.
• Permanent injunction. Court order after full trial permanently restraining infringement.
• Damages and account of profits. Compensation for loss suffered or disgorgement of the infringer’s profits.
• Seizure and destruction. Court‑ordered seizure, recall or destruction of infringing products and tooling.
• Customs border measures. Application to Danish customs authorities to detain suspected infringing goods at the border.
• Publication of judgment. Court may order publication of the decision at the infringer’s expense.

Eligibility and Prerequisites

Before filing any enforcement action, the claimant must satisfy several threshold requirements. Only the registered patentee or an exclusive licensee (with appropriate contractual standing) may bring infringement proceedings. Non‑exclusive licensees generally lack standing unless the patent holder joins or authorises the claim. Foreign patent owners have full standing but must appoint Danish counsel for service and filings.

The patent must be in force, renewal fees paid, no lapse recorded on the DKPTO register, and the claims must cover the territory of Denmark. For European patents, the Danish validation must be complete. Utility models registered in Denmark may also be enforced under analogous provisions.

A common tactical question is whether main infringement proceedings may be initiated while patent opposition proceedings in Denmark are pending before the DKPTO or the European Patent Office. The answer is generally yes: Danish courts have jurisdiction over infringement regardless of parallel opposition proceedings. However, a pending opposition can affect the court’s willingness to grant a preliminary injunction, because the validity of the patent is less certain. Early indications from 2026 case law suggest courts will weigh the strength of validity arguments more carefully at the PI stage, a point addressed in detail below.

Step‑by‑Step Procedure for Enforcing a Patent in Denmark

The following numbered steps outline the patent infringement procedure Denmark‑based and international rights‑holders should follow. The procedure applies to both preliminary injunction applications and full main proceedings.

Step 1, Conduct Pre‑Action Due Diligence and Preserve Evidence (Day 0–7)

The moment infringement is suspected, the priority is evidence preservation. Delay of even a few days can allow an infringer to destroy samples, alter product configurations or relocate stock.

1. Verify patent status. Obtain a certified extract from the DKPTO register confirming the patent is in force, renewal fees are current and the claims cover the suspected infringing activity.
2. Confirm chain of title. Assemble assignment deeds, licence agreements and any amendments recorded at the DKPTO. Foreign assignees should ensure the register reflects the current owner.
3. Identify and document the infringement. Purchase or obtain samples of the accused product. Capture screenshots of online listings, marketing materials and packaging with metadata intact. Photograph physical evidence with time stamps.
4. Prepare preliminary claim charts. Map each independent patent claim element against the features of the accused product or process. This chart forms the backbone of both the PI application and the main claim.
5. Consider a pre‑action letter. Sending a cease‑and‑desist letter is not a statutory requirement in Denmark, but it can serve tactical purposes: it may prompt voluntary compliance, trigger a declaratory judgment counter‑action by the alleged infringer, or provide evidence of the infringer’s knowledge. Decide on a case‑by‑case basis, if urgency demands a surprise PI, skip the letter.

Step 2, Apply for a Preliminary Injunction in Denmark (Day 1–21)

A preliminary injunction Denmark patent holders seek is the fastest route to stopping ongoing infringement. The application is filed with the Maritime and Commercial Court and must demonstrate:

• Title to the patent. Certified register extract and chain‑of‑title documentation.
• Prima facie infringement. Claim charts supported by product samples and, ideally, an expert affidavit showing how each claim element is met.
• Urgency and balance of hardships. The applicant must show that waiting for a full trial would cause disproportionate harm and that the balance of interests favours interim relief.
• Willingness to post security. The court will typically require the applicant to provide security (a bond or bank guarantee) to compensate the defendant if the injunction is later found to have been wrongly granted.

Applications are normally heard inter partes (with notice to the defendant). Truly ex parte orders, granted without hearing the other side, are rare in Danish patent practice and reserved for cases where notice would defeat the purpose of the relief. The court may schedule an urgent hearing within 7 to 14 days of filing, though complex matters can take up to 21 days.

Industry observers expect the early‑2026 Supreme Court guidance on validity presumptions to make courts marginally more willing to grant PIs where the patent has survived opposition or re‑examination, because the validity presumption is now stronger at the provisional stage. Rights‑holders whose patents face a pending opposition should, however, treat PI applications with particular caution, the court may view unresolved invalidity challenges as weakening the prima facie case.

Step 3, Initiate Main Infringement Proceedings (Day 0–90+)

Whether or not a PI has been sought, the claimant will normally file a statement of claim (stævning) with the Maritime and Commercial Court. The claim should set out:

1. The patent(s) relied on and the claims alleged to be infringed.
2. A detailed description of the infringing acts, supported by claim charts, product analysis and expert evidence.
3. The remedies sought, typically a permanent injunction, damages (or account of profits), destruction of infringing products, and costs.

If a PI is already in place, many plaintiffs file the main suit promptly to demonstrate good faith and prevent the court from lifting the interim order. Where no PI was sought, for example, because the infringement is historical and the product has been withdrawn, the main claim proceeds on a standard track.

The defendant will file a defence (svarskrift) and may counterclaim for invalidity of the patent. The court will then set a timetable for further written submissions, expert evidence and an oral hearing. First‑instance trials in patent cases typically reach judgment within 9 to 18 months of filing, though technically complex disputes can extend beyond this range.

If DKPTO opposition proceedings are running in parallel, the court has discretion to stay the infringement action pending the opposition outcome, although stays are not automatic. Coordinate the two tracks carefully: evidence gathered for the court case can often support the opposition defence, and vice versa.

Step 4, Enforce the Judgment and Manage Appeals (Post‑Judgment)

Once a judgment or permanent injunction is obtained, enforcement may include:

• Seizure and destruction orders. The court can order bailiffs (fogeden) to seize infringing stock, moulds and tooling. These orders are executed by the enforcement court.
• Customs notifications. File an application with Danish customs under the EU Customs Regulation to detain suspected infringing goods at the border. This is particularly effective where the infringer imports from outside the EU.
• Damages collection. If the defendant does not pay voluntarily, initiate enforcement proceedings through the bailiff’s court.
• Appeals. The losing party may appeal first‑instance decisions to the High Court. With leave, a further appeal to the Supreme Court is possible. Injunctions generally remain in force during appeal unless the appellate court grants a stay, which typically requires the appellant to post security.

Required Documents and Evidence Checklist

Gathering the right evidence early is the single most important factor in how to enforce a patent in Denmark successfully. The table below sets out the core documents needed for both PI applications and main proceedings.

Practical Evidence Ordering for a PI Application

When time is short, prioritise evidence preparation in this sequence:

1. Immediate preservation. Secure product samples, screenshots and metadata before the infringer can alter or withdraw them.
2. Chain of custody. Document who obtained each item, when, and how it has been stored.
3. Claim charts and expert affidavit. Commission an expert to prepare or verify the infringement mapping. The affidavit should address both infringement and, briefly, validity, given the 2026 Supreme Court emphasis on the validity presumption at PI stage.
4. Provisional witness statements. Prepare short, fact‑specific statements from key witnesses (e.g., the person who purchased the accused product).

Enforcement Timeline and Key Deadlines

The enforcement timeline varies significantly depending on whether the rights‑holder seeks a preliminary injunction, proceeds directly to main proceedings or pursues both tracks. The table below provides indicative timelines based on current Maritime and Commercial Court practice.

The shortest realistic path from discovery of infringement to an interim injunction is approximately two to four weeks, achievable only with rapid evidence gathering and an experienced litigation team. The median path from filing a main claim through to first‑instance judgment is closer to 12 months. Rights‑holders should factor appeal timelines into their commercial planning: a determined defendant may extend the dispute to three years or more across all instances.

Enforcement Costs, Fees and Tax Considerations

Patent enforcement costs in Denmark vary widely depending on the complexity of the dispute, the number of patents asserted, the volume of expert evidence and whether a preliminary injunction is sought. The table below provides indicative cost bands. All figures are approximate and should be verified against current DKPTO and court fee schedules.

Regarding tax treatment, damages awarded in patent infringement proceedings are generally treated as taxable income for the recipient under Danish tax law. VAT typically does not apply to damages payments, though specific fact patterns, for example, where damages are characterised as a licence fee, may warrant separate tax advice. Rights‑holders should consult a Danish tax adviser before structuring settlement or damages claims.

Patent Enforcement Denmark 2026: What Changes and Why It Matters

The most significant development for patent enforcement Denmark practitioners face in 2026 is the Danish Supreme Court’s refined approach to validity assessment in preliminary injunction proceedings. In a landmark decision published in early 2026, the Supreme Court established a stronger validity presumption for granted patents when courts assess PI applications. The likely practical effect is that patentees whose patents have survived opposition, re‑examination or prior judicial scrutiny will find it easier to satisfy the prima facie validity requirement at the PI stage.

The AIPPI summarised the ruling as establishing that a granted patent carries a presumption of validity that the alleged infringer must overcome with specific, credible invalidity arguments, rather than merely raising theoretical prior‑art objections. For rights‑holders, this shifts the tactical balance in favour of seeking early injunctive relief, particularly where the patent has a clean prosecution history.

However, industry observers note several caveats:

• Patents under active opposition. Where an opposition is pending before the DKPTO or the EPO, the validity presumption is weaker. Courts may decline to grant a PI or impose a higher evidentiary burden on the patentee.
• Unitary Patent and UPC interactions. Denmark participates in the Unitary Patent system. Rights‑holders now face a strategic choice between enforcing nationally (in the Maritime and Commercial Court) and commencing proceedings in the Unified Patent Court. National proceedings offer familiarity and speed; UPC proceedings offer pan‑European injunctions but carry the risk of a centralised revocation. The EPO’s published national measures confirm Denmark’s participation in the Unitary Patent regime.
• Parallel proceedings risk. Filing in both the UPC and the Danish national court simultaneously raises procedural complexity. Early cross‑border counsel input is essential to avoid conflicting outcomes or procedural objections.

A practical tactical checklist for 2026:

1. Assess whether the patent has survived any validity challenge (opposition, re‑examination, prior litigation). If so, the 2026 validity presumption strengthens a PI application.
2. If the patent is subject to a pending opposition, weigh the risk that the court may decline the PI or require enhanced evidence. Consider proceeding directly to main proceedings instead.
3. Evaluate whether national enforcement or UPC proceedings (or both) best serve the commercial objective. Factor in the scope of the injunction needed and the defendant’s asset locations.
4. Budget for the possibility that the defendant will challenge validity as a defence in any forum, prepare invalidity evidence defensively from the outset.

Common Pitfalls and How to Avoid Them

• Late or incomplete evidence preservation. Failing to secure product samples, screenshots and metadata immediately can fatally weaken both PI and main proceedings. Begin forensic preservation on day zero, documenting chain of custody throughout.
• Overreliance on expert reports without physical evidence. An expert affidavit is persuasive only when supported by tangible evidence, actual product samples, detailed photographs and independently verifiable data. Claim charts alone, without demonstrable products, are rarely sufficient.
• Filing a PI without assessing opposition and invalidity risk. If the patent faces a pending opposition or has known prior‑art vulnerabilities, a PI application may fail and generate adverse cost consequences. Conduct a thorough prior‑art search and coordinate with any pending DKPTO proceedings before applying.
• Underestimating bond and security requirements. Courts routinely require the PI applicant to post security for the defendant’s potential losses. Failure to arrange funding in advance can delay or prevent the injunction. Plan contingency funds and secure bank guarantees before filing.
• Ignoring the UPC and Unitary Patent dimension. Pursuing national enforcement without considering UPC options, or vice versa, can result in incomplete protection or jurisdictional conflicts. Obtain cross‑border counsel input at the earliest stage to map the optimal enforcement strategy.

Conclusion

Knowing how to enforce a patent in Denmark requires a clear understanding of the courts, the procedural steps, the evidence needed and the costs involved. The 2026 Supreme Court guidance on patent validity presumptions at the preliminary injunction stage has tilted the tactical landscape in favour of well‑prepared rights‑holders, but only for those who act quickly, preserve evidence meticulously and coordinate national proceedings with the broader Unitary Patent and UPC framework. Whether the objective is an emergency injunction to block a product launch or a full damages claim after years of infringement, the roadmap above provides the procedural foundation.

For enforcement situations that require immediate action, connecting with experienced Danish patent litigation counsel through the Global Law Experts lawyer directory is the recommended next step.

Sources

1. Danish Patent and Trademark Office (DKPTO)
2. Business in Denmark (Virk), Patents Guide
3. Plesner, Supreme Court Decision Note (January 9, 2026)
4. EPO, National Measures: Denmark (Unitary Patent / UPC Interaction)
5. AIPPI, Danish Supreme Court Validity Presumption Note
6. CBS Working Paper, Market Entrance, Patents and Preliminary Injunctions
7. Bardehle, Preliminary Injunction in Patent and Utility Model Cases