This study aims to analyze the application of criminal law aspects to narcotics sales transactions in Indonesia, as well as examine the criminological factors that influence the occurrence of these crimes. This study focuses on Decision Number 99/Pid.Sus/2024/PN Kbu, which sentenced defendant Didi Handi Bin Sabri because he was proven to be an intermediary in the sale and purchase of methamphetamine. This study uses an empirical approach method with data collection techniques from interviews and court decisions. The informants in this study were judges at the Kotabumi District Court. The results of the study indicate that the application of criminal law in this case is in accordance with the provisions of Law Number 35 of 2009 concerning Narcotics, specifically Article 114 paragraph (1), which regulates criminal sanctions for perpetrators of Class I Narcotics distribution. The sentence imposed by the panel of judges is considered appropriate and proportional, taking into account the defendant's role in the network, the severity of the act, and mitigating circumstances. From a criminological perspective, the defendant's involvement in this crime was influenced by various factors, including economic pressure, social influences, drug dependence, and low legal awareness. This study recommends comprehensive efforts to combat drug crime, employing not only a repressive approach but also preventive and rehabilitative approaches to break the chain of drug trafficking at its root.