This study aims to analyze the strategic role of Main Gate Guards (P2U) at the Class I Madiun Penitentiary in preventing the entry of prohibited items, such as narcotics, sharp weapons, and illegal communication devices, which have the potential to disrupt security and the inmate development process. This study uses an empirical legal approach with data collection techniques including direct observation and interviews with P2U officers, as well as literature review.
The results indicate that P2U plays a vital role as the frontline in the security system, including inspections of people, goods, and vehicles entering and leaving the prison. However, the implementation of P2U duties faces several obstacles, such as limited personnel, a lack of modern detection equipment, and minimal technical and procedural training. To increase the effectiveness of prevention, this study recommends optimizing P2U functions through human resource development, upgrading security equipment, and ongoing development based on clear standard operating procedures. This research contributes to strengthening the correctional supervision system and creating a safe prison environment that supports the holistic rehabilitation process for inmates.

Keywords: Main Gate Guard (P2U), Madiun Class I Prison, Prohibited Items,
Security System