Background: People with chronic illnesses such as HIV infection face many health status outcomes in the correctional settings. The current study aimed at investigating multiple determinants of HIV medication adherence among patients with HIV. Methods: Focus group discussion (FGD) was conducted on inmates of Ghezel-hesar Prison in Karaj, Alborz province, Iran, to investigate the barriers and facilitators of adherence to antiretroviral therapy (ART) in January 2015. The purposive sampling method was employed to recruit seven male prisoners with HIV infection. Results: Participants reported illegal drug use, poor education in HIV treatment, side-effects of anti-retroviral drugs, treatment interruption, drug interferences, fear of hangover, poor diet, poor socioeconomic background, hopelessness, depression, not believing in the treatment, rejection and lack of social support, stigma, compulsory rest in the yard, lack of tendency toward visiting psychiatrists, lack of familial support, forgetfulness, and not receiving complementary drugs as the barriers to adherence to ART. In addition, the facilitators were physician-patient good relationship, physician's compassion, counseling services for the patients, education of patients regarding HIV treatment necessities, peer education, informing patients about their CD4 levels, education of correctional staff to show courtesy in the treatment of patients, timely methadone therapy, and improved diet. Conclusions: Providing welfare programs and education of inmates with HIV infection regarding the adherence to ART may play a prominent role in the treatment of such patients. Training correctional staff regarding the significance of HIV treatment and adherence to ART can also be effective in the treatment of prisoners with HIV infection.