<![CDATA[Narcotics abuse remains a major problem at Class I Tangerang Correctional Institution, which houses the largest number of narcotics offenders (1,076 of 1,598 inmates). This study aims to describe the application of Islamic Religious Values (IRV) in the personality development program, to understand the process of internalizing Islamic Religious Values and the character formation of narcotics offenders, and to identify its supporting and inhibiting factors. The study used a descriptive qualitative approach with in-depth interviews, non-participant observation, and documentation involving three narcotics offenders as main informants and two program officers as supporting informants. Data were analyzed using the Miles and Huberman interactive model, and data validity was tested through source triangulation, technique triangulation, and member checking. The findings show that IRV is applied through the Santri At-Tawabin program, which consists of routine religious study six days a week, worship practice, and habituation, with the value of worship appearing most prominently compared with faith and morals. The internalization process appears in the stages of value transformation, transaction, and transinternalization, but it is uneven: transformation is the clearest, transaction is limited because inmates feel reluctant to consult personally, and transinternalization appears in habituated worship but has not been tested after release. Supporting factors include personal awareness and motivation, the exemplary conduct of officers, the coaching environment, habituation of religious activities, and family support. Inhibiting factors include reluctance and limited interaction with officers, difficulty understanding religious material, the psychological burden on inmates, limited officers, teachers, and facilities, and the challenge of sustaining change after release.]]>
