['Antiretroviral regimens for HIV-infected patients require strict adherence. Untreated depression has been associated with medication nonadherence. We proposed to evaluate the effect of antidepressant treatment (ADT) on antiretroviral adherence.', 'Data were retrieved for HIV-infected patients seen at an urban health care setting (1997-2001) from chart review and administrative and pharmacy files. Antiretroviral adherence was determined for depressed patients stratified by receipt of and adherence to ADT. Antiretroviral adherence was compared before and after initiation of ADT.', 'Of 1713 HIV-infected patients, 57% were depressed; of those, 46% and 52% received ADT and antiretroviral treatment, respectively. Antiretroviral adherence was lower among depressed patients not on ADT (vs. those on ADT; P = 0.012). Adherence to antiretroviral treatment was higher among patients adherent to ADT (vs. those nonadherent to antidepressant treatment; P = 0.0014). Antiretroviral adherence improved over a 6-month period for adherent, nonadherent, and nonprescribed ADT groups; however, the mean pre- versus post-6-month change in antiretroviral adherence was significantly greater for those prescribed antidepressants.'] Does antidepressant treatment improve adherence to antiretroviral therapy among depressed HIV-infected patients?