This thesis discusses the application of the Unus Testis Nullus Testis
principle in cases of fornication. This study aims to determine whether the Unus
Testis Nullus Testis principle can not be applied in all criminal cases and to find
out how to overcome difficulties in the application of the Unus Testis Nullus
Testis principle. This research is a normative legal research that focuses on
positive legal norms in the form of statutory regulations. This research uses a legal
approach and case studies. The type of data in this research is secondary data with
primary and secondary legal materials. Data collection techniques using literature
study and interviews and data analysis techniques using deductive thinking
methods. The principle of the Nullus Testicle Unus Testis contained in Article
185 paragraph (2) of the Criminal Procedure Code, in terms of the decision
number 48.Pid.Sus / 2017 / PN.Plg, the Judge seems unable to apply the Unus
Nullus Testis. The testicular principle, this is due to the limited evidence in this
case. In this regard, law enforcers, especially the Public Prosecutors, can optimize
legal evidence according to law in addition to witness testimony as stated in
Article 184 paragraph (1) of the Criminal Procedure Code.