This paper compares antiretroviral outcomes of patients at a primary care clinic with those previously reported at HIV specialty clinics and examines risk factors for treatment failure. A retrospective medical record review was undertaken at an academic primary care practice in Baltimore, Maryland. One hundred and twenty-three patients were included who had not previously received HAART and who were started on a regimen that included a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor and at least one other new antiretroviral medication. HIV RNA levels, CD4 lymphocyte counts, missed appointment rate, HAART regimen, demographic variables, and their association with the achievement of a viral RNA of 500 or less at 7-14 months were analyzed. Forty-seven per cent of the patients had an HIV RNA level of 500 or less at 7-14 months after initiation of HAART. Factors associated with treatment failure included missed appointment rate, injection drug use and previous exposure to antiretroviral medication. On multivariate analysis, only missed appointment rate and lower baseline CD4 lymphocyte count were independently associated with treatment failure. The antiretroviral outcomes of patients started on HAART by experienced health care providers in this primary care practice were comparable to those reported in specialty clinics. As with previous reports, most patients did not maintain viral suppression. Missed appointment rate was the most important risk factor for treatment failure.