Background and Aim:  AIDS is a lethal disease, for which there is no treatment or any vaccine to prevent it. The injection-drug use and unprotected sexual behavior are two factors important  in HIV transmission. This study was conducted to determine changes in high-risk sexual and injection-drug use behaviors associated with HIV among drug users referring to Methadone Maintenance Treatment centers in Shiraz, Iran.

Materials and Methods: This before-after interventional study with no control group included drug-users (n=694) referring to all the 7 MMT centers in Shiraz, Iran in 2009. The data were collected by interviewing patients and using a questionnaire. The software used for data analysis was SPSS 15, the statistical test being the Wilcoxon test.

Results: The average age of the clients was 36.5 ± 9.5 years. Most of them were males (% 92.1) and single (% 43.1). 37.3 % of them being injection-drug users. The proportion of the injection-drug users having had at least one shared injection one week before referring to an MMT center was 23.3%, which decreased to 9.2% after one week. Analysis of the data also showed that 25.2% of the addicts had had at least one unprotected sexual contact during the previous month; the proportion decreased to 21.0% one month after referring to an MMT center. The reductions in the mean numbers of both shared injections and unprotected sexual contacts were statistically significant (p <0.001).

Conclusion: Considering the effectiveness of the MMT centers in reducing risky behaviors of injection-drug users, it is essential to expand these centers at both the national and regional levels quantitatively and qualitatively and encourage drug-users to refer to them and seek help. This will help greatly in the prevention of HIV.