Purpose: Assessing the economic burden of HIV/AIDS can help quantify the effect of the epidemic on a population and assist policy makers in allocating public health resources. The purpose of our study was to estimate the economic burden of HIV/AIDS in the United States and provide race/ethnicity specific estimates. Methods: We conducted an incidence-based cost-of-illness analysis to estimate the lifetime cost of HIV/AIDS resulting from new infections diagnosed in 2002. Data from the HIV/AIDS Reporting System of the Centers for Disease Control and Prevention were used to determine stage of disease at diagnosis and proportion of cases by race/ethnicity for the annual incidence estimate of 40,000 new infections. We used standard methods to estimate lifetime direct medical costs and indirect costs (mortality-related productivity losses) using cost, life expectancy, and antiretroviral therapy (ART) utilization data from the literature. We conducted sensitivity analyses to assess uncertainty in ART utilization, life expectancy, and the impact of missing data. Results: The cost of new HIV infections in the United States in 2002 is estimated at $36.4 billion, including $6.7 billion in direct medical costs and $29.7 billion in productivity losses. Direct medical costs per case were highest for whites ($180,900) and lowest for blacks ($160,400). Productivity losses per case were lowest for whites ($661,100) and highest for Hispanics ($838,000). In sensitivity analysis, universal use of ART and more effective ART regimens decreased the overall cost of illness. Conclusions: Direct medical costs and productivity losses of HIV/AIDS resulting from infections diagnosed in 2002 are substantial. Productivity losses far surpass direct medical costs and are disproportionately borne by minority races/ethnicities. These results were influenced by later diagnoses and lesser access to ART for minorities. Our analysis underscores economic benefits of more effective ART regimens and universal access to ART.