Patent cases are heard by the specialised IP courts in Istanbul, Ankara and Izmir. As specialised IP court judges do not have a technical background, expert reports are essential in patent litigation. As a general practice, the courts obtain reports concerning the alleged infringement, invalidity claim or compensation claim from court-appointed experts during a trial. The parties can submit their own private expert reports to address the technical aspect of the dispute in addition to the reports provided by the court-appointed experts.(1)

Private expert reports help to clarify the subject matter and technical details of inventions. However, parties can submit objections and such reports may contradict an expert report.

Given the number of expert reports provided in patent litigation, cross-examination is vital as it allows the courts to gain an understanding of the matter at hand. The judge may therefore decide to hear private and court-appointed experts at the request of the parties. In addition, parties may request the court's consent for their private or in-house technical experts to attend the hearing.

The court will render an interim decision notifying the parties to a dispute of the hearing date and grant consent for parties' technical experts to attend. The court may also request that the parties submit a list of questions for the court-appointed and private experts before the hearing.

As set out in Article 152 of Procedural Law 6100, a party's attorneys can direct their questions to the court-appointed and private experts, whereas questions to be asked by the experts must be directed through the judge. Objections to such questions will be evaluated, accepted or rejected at the judge's discretion.(2)

Private expert reports and cross-examination hearings enable judges (who do not have a technical background) to understand the technical details of patent litigation. Despite the reluctance of some judges to schedule cross-examination hearings, there have been some notable examples of such hearings in patent litigation, which have encouraged parties to request such procedures in complex patent disputes.

For further information on this topic please contact Muazzez Korutürk or Okan Çan at Deris IP Attorneys by telephone (+90 212 252 6122) or email ( or The Deris website can be accessed at


(1) Article 293 of Procedural Law 6100 stipulates that parties can obtain and submit as evidence scientific reports from experts in the field of the matter subject to court action. On request of the parties or at its own discretion, the court may decide to hear the private expert who prepared the report and direct questions thereto. The expert report will not be considered if the private expert fails to attend the hearing.

(2) Article 152 of Procedural Law 6100 stipulates the method for questioning private experts, witnesses and other third parties during a hearing. Accordingly, attorneys can direct questions to private experts who attend a hearing in line with the disciplinary requirements of the court.

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