OBJECTIVES: To analyze the cost of MMT treatment for patient with substance use disorder. METHODS: This was a retrospective study involving 185 opiate dependence patients who were receiving MMT treatment program in Malaysian’s government hospitals starting December 2005 until February 2010. The study was done from the provider perspective using activity based costing that includes both capital and variable cost associated with MMT program. RESULTS: Most of the respondents were male (99%) with mean age of 38.5 years. Most (72.5%) of them were Malay and 50.5% working in semi or unskilled manual job with basic salary less than MYR1000 (US$312). Most  (99.5%) were smoker with history of heroin addiction of more than 10 years. The median length of MMT treatment was 14 months. Fifty-seven percent of the patients were suffering from chronic disease. The capital cost for MMT program was US$8013.16 and the variable cost of providing a month of treatment per patient was US$50.43. Approximately 47.19% of this was for methadone and personnel cost accounted for 31.94%. The variable cost was statistically higher (p<0.05) in patients present of chronic disease.  CONCLUSIONS: This study estimated the variable cost of MMT treatment per patient in Malaysia (US$50.43/month) is less expensive compare USA (US$220/month, Jones et al., 2009). These cost data may be useful to policymakers and researchers for further developing the program.