Objective: Despite numerous advances in antiretroviral therapy (ART) for HIV patients over the past decade, many patients fail to receive appropriate ART. This study sought to identify demographic factors associated with failure to receive guideline-concordant ART. Methods: Data was extracted from the 2000-2005 NAMCS. HIV patients were defined as those that received at least one antiretroviral during an ambulatory care visit. Data collected included patient age, gender, race, ethnicity, geographic region, insurance status, and medications. Antiretroviral regimens were evaluated for appropriateness according to antiretroviral guidelines published by the Department of Health and Human Services. Appropriate and inappropriate regimens were compared using the Chi-square or Fisher's Exact test. Results: Antiretroviral therapy was mentioned in 107 of 156,627 visits. These patients had a median (25th-75th percentile) age of 45 (38-54) years, 66% were male, 64% were white, and 42% had Medicaid/SCHIP. Only 58% of patient visits documented appropriate ART. These consisted of two nucleoside reverse transcriptase inhibitors (NRTIs) plus one non-nucleoside reverse transcriptase inhibitor (NNRTI) (36%), two NRTIs plus two protease inhibitors (PIs) (26%), or two NRTIs plus PI (11%). Inappropriate monotherapy was commonly reported: NRTI (30%), PI (16%), or NNRTI (12%) monotherapy. Patients were less likely to receive appropriate therapy if they were =50 years of age (23% vs. 49%, p=0.003) or had Medicare (5% vs. 23%, p=0.005). All Asian patients in the surveys received inappropriate therapy (p=0.007 vs. non-Asians). Comparisons of appropriate ART use among females vs. males (30% vs. 47%, p=0.08) and whites vs. non-whites (63% vs. 67%, p=0.6); failed to achieve statistical significance. However, the post-hoc power for these statistics was only 42% and 6%, respectively. Conclusion: Nearly half of patients in the 2000-2005 NAMCS received suboptimal HIV therapy. Asian patients, Medicare patients, and those patients over the age of 50 years were significantly less likely to receive guideline-endorsed therapies.