Purpose To estimate relative survival (RS) after human immunodeficiency virus (HIV) diagnosis, by race/ethnicity and county-level socioeconomic status (SES). Methods We estimated 5-year RS by age, race/ethnicity, transmission category, sex, diagnosis year, CD4 count, and by county-level SES variables from the U.S. Census. Data, from the national HIV/AIDS Reporting System, were for HIV-infected persons ages ≥13 years (diagnosis during 1996–2003 and follow-up through 2005). We calculated RS proportions by using a maximum likelihood algorithm and modeled the relative risk of excess death (RR) using generalized linear models, with poverty as a random effect. Results For men, RS was worse in counties with larger proportions of people living below the 2000 U.S. poverty level (87.7% for poverty of ≥20% vs. 90.1% for poverty of <5.0%) and where unemployment was greater (87.8% where unemployment > 7.1% vs. 90.5% where unemployment < 4.0%). The effects of county-level SES on RS of women were similar. In multilevel multivariate models, RR for men and women within 5 years after an HIV diagnosis was significantly worse in counties where 10.0–19.9% (compared with <5.0%) lived below the poverty level (RR = 1.3 95% CI 1.2–1.5 and RR = 1.8 95% CI 1.4–2.2, respectively). Conclusions RS was worse in lower SES areas. To help address the impact of county-level SES, resources for HIV testing, care, and proven economic interventions should be directed to areas with concentrations of economically disadvantaged people.