This study is an observational cross-sectional study aimed to examine the possible demographic and social characteristics of patients enrolled at the Methadone Maintenance Therapy Adherence Clinic (MMTAC) in Malaysia. Medical records from year 2009 - 2011 were Reviewed. Demographic, social characteristics and laboratory examinations such as age, gender, race, clinic attendances and urine analysis were recorded. Subjects were selected by means of convenient sampling but based on the specified inclusion and exclusion criteria. Data were analyzed by either Chi-square test, Fisher's exact test Mann-Whitney U-test, with the limit of significance was set at p < 0.05. Demographically, this study found that the ratio of Malays, Chinese and Indian enrolled to the MMTAC program is similar to the distribution of races in Malaysia. Their starting age for drug use was between 14-35 years and the age to enrolment between 30-58 years. Socially, many are unemployed, lowly educated and married. Most are drug users with a high percentage of HCV accompanied with impaired liver function. Retention rate was 87% but illicit drug use was at 57.50%. However, percentage of employment increased significantly after therapy. The study managed to identify several demographical and social distributions of patients attending the MMTAC. Although attendance rate was high, many were on illicit drug use. Nevertheless, employment rate improved significantly.