Background: Few studies have explored factors associated with clinical decision-making and HIV testing in outpatient departments’ (OPD). Using the Eisenberg’s model of physician decision-making as contextual framework, we examined the impact of provider characteristics, and provider-patient relationship on HIV testing decisions made in OPDs. Methods: Data from the National Hospital Ambulatory Medical Care Survey (NHAMCS), 2009-2011 were pooled for those aged 13-64 years. We conducted weighted multi-stage survey analyses using SAS 9.4. Results: HIV testing occurred during 2.7 million visits representing 1.32% of all OPD visits. Decreased HIV testing rates were found in 2010 and 2011 compared to 2009. HIV testing was highest among patients seeking preventive care (3.2%), aged 20-29 years (3.0%), African Americans (2.5%), Hispanics (2.4%) and the uninsured (2.3%). Multivariate logistic regression showed that patients visiting primary care facilities were least likely to be tested [OR 0.59 (0.40-0.86)], as were patient visits occurring in the West [OR 0.42 (0.20-0.87)] and Midwest [0.45 (0.25-0.81)] compared with the Northeast. Patients visiting government facilities [OR 1.91 (1.11-3.27)] had higher HIV testing rates compared with those visiting non-profit facilities and facilities in metropolitan areas. New patients [OR 2.84 (2.04-3.96)], uninsured [OR 2.60 (1.55-4.40)] and Medicaid patients [OR 2.19 (1.27-3.80)] as well as African Americans [OR 2.31 (1.61-3.32)] all had higher odds for getting an HIV test. Conclusions: The outpatient department is a convenient location for HIV testing, however, discriminatory decision-making across different groups of patient needs closer investigation to expand HIV screening in health care facilities as recommended by CDC.