Introduction: Methadone Maintenance Treatment (MMT) is the commonly used intervention for opioid dependents among Malays in FELDA settlements. However, relapse is common. Since majority of Malays are Muslims, Islamic Rehabilitation Intervention Module (ISRIM) using Health Belief Model (HBM) can be implemented as an intervention for reduction of relapse among opioid dependents in FELDA community. The objective of this study were to develop, implement and evaluate the effectiveness of ISRIM in the reduction of relapse among opioids dependent Malay males in FELDA communities in Jengka, Pahang. Methods: A single blind, cluster randomized controlled trial utilizing simple randomization was conducted, involving 10 MMT clinics. Intervention group received ISRIM for one session per week for four consecutive weeks, while control group were put on wait-list. Outcome was relapse, measured monthly for 6 months follow-up by the positive urine for drugs rapid test. Generalized Estimating Equations (GEE) was used as the main effectiveness analysis. Intention-to-treat (ITT), per protocol (PP) analysis, interaction terms, construct terms and key assumption terms were utilized. Results: Individual participation rate was 88.3%. All group comparisons at baseline were not significant (p>0.05). Cumulative relapse after 6-months follow-up for intervention and control group was 13.8% and 31.2%. There was significant difference in relapse between baseline, post-inter-vention and 6-months follow-up within intervention and control group (Q=29.06 vs 61.39,p