Objective: This study was conducted to assess the effects of Methadone Maintenance Therapy (MMT) and buprenorphine-naloxone Maintenance Therapy (BNX) on the Quality of life (QoL) of opiate abusers. Methods: The QoL status of opioid-dependent patients was assessed using the WHOQOL-BREF questionnaire. It is a cross-sectional study involving a total of 108 patients who received MMT or BNX therapy in Malaysia from May 2011 to September 2011. Results: A statistically significant difference in the overall QoL and psychological aspect among patients on MMT was observed. On the contrary, the scores of overall QoL and quality of social relationship for BNX group were higher in patients with lower dosage. Conclusion: The comparison between patients on high dose MMT and high dose BNX exhibited significant difference in the overall QoL especially in psychological, social relationship and environment domains, with the high dose MMT group having better mean score.