To explore the influence of psychiatric distress and substance use on viral load suppression in HIV-infected patients taking ART we analyzed socio-demographic characteristics, CD4+ cells count and viral loads, the Symptom Check List-90 and the Addiction Severity Index of 75 patients who had taken ART for at least 6 month. Using viral load data as the marker of ART success, we divided the sample into two groups. Comparison of the groups showed that education, marriage, and female gender are predictors of optimal viral load suppression. Overall results failed to demonstrate substance use and psychiatric distress as predictors of viral load suppression.