BACKGROUND/AIM: Widespread use of antiretroviral treatment (ART) has led to decrease in the incidence of HIV/AIDS-related mortality. Besides the availability of ART, medication adherence is essential for treatment success. There is a scarcity of data reported from Turkey regarding ART adherence among people living with HIV/AIDS (PLWHA). Therefore, this study was undertaken to determine medication adherence and related factors among PLWHA in Turkey. MATERIALS AND METHODS: The sample consisted of 158 PLWHA, who were being followed up at Infectious Diseases Outpatient Clinic of Hacettepe University Hospital. Data were collected using an individual questionnaire and the Turkish version of the Morisky Medication Adherence Scale. RESULTS: The median patient age was 38 years, 80.4% were male, and 51.3% were married. The median duration of both HIV infection and ART was 3 years. Sixty-one percent used two drug regimens. Sixty-one percent were highly adherent to ART while 37.9% were moderately adherent. The absence/presence of social support resources, disease duration, ART duration, and being informed about the ART regimen were statistically associated with medication adherence. CONCLUSION: Our results suggest that medication adherence is excellent among Turkish PLWHA. Interventions, including effective social support, and continuous counseling about ART, might further boost the adherence of PLWHA