Application of double jeopardy
Recent Supreme Court precedent

In South Korea, in accordance with the prohibition of double jeopardy, once a patent trial decision on the merits is rendered and becomes final and conclusive, no person may demand a subsequent trial based on the same facts and evidence with the Intellectual Property Trial and Appeal Board (IPTAB).(1)

Application of double jeopardy

The advantages of the prohibition of double jeopardy include the following:

  • It prevents conflicting trial decisions relating to the same matter.
  • It prevents the burden of a respondent having to respond to the same case more than once.
  • The IPTAB need hear a case only once, thus reducing the administrative burden placed on government institutions.

However, the disadvantage of the prohibition of double jeopardy is that the inherent interests of parties seeking a decision could potentially be infringed. For example, if there are a number of parties that each have their own interests in seeking the invalidation of the same patent, each should have the freedom to bring an invalidation action, but this may not be possible.

The advantages described above can generally be understood as pertaining to the preservation of patent stability and the promotion of judicial economy. While achieving these aims, the prohibition of double jeopardy applies only to cases where the facts and evidence are identical, so as to not infringe the inherent interests of any party wishing to have their case heard via trial. Such prohibition, however, does not apply to decisions to dismiss trial requests for being unlawful, meaning that other parties can still request a trial on the same grounds, regardless of the original dismissal decision.

Recent Supreme Court precedent

The prohibition of double jeopardy in relation to dismissal decisions was recently contested at the Supreme Court.(2)

In the earlier instance Patent Court trial, it was ruled that even if there is a decision to dismiss a trial request for being unlawful, the prohibition of double jeopardy should still be applied. The reason given reason for this was that a substantive judgment regarding lack of inventiveness is still made when a trial is dismissed after judging the identity of the evidence.

However, faithful to the provisions stipulated in the Patent Act, the Supreme Court held that the prohibition of double jeopardy does not apply to dismissal decisions, as such judgments could affect third parties' rights to request a trial.

As a result, it may be concluded that the prohibition of double jeopardy does not apply to any dismissal decisions, regardless of whether substantive judgment was carried out in reaching the decision.

For further information on this topic please contact Young-min Kim at NAM & NAM by telephone (+82 2 753 5477) or email ([email protected]). The NAM & NAM website can be accessed at


(1) For further information please see "Timing of Double Jeopardy Judgement in Patent Trials".

(2) Case 2021HU100777; 3 June 2021.