OBJECTIVE: To estimate association between educational attainment and risk of HIV diagnosis, response to HAART, all-cause, and cause-specific mortality in Denmark in 1998-2009. DESIGN: Prospective, population-based cohort study including 1277 incident HIV-infected patients without hepatitis C virus or intravenous drug abuse identified in the Danish HIV Cohort Study and 5108 individually matched population controls. METHODS: Data on educational attainment, categorized as low, medium, or high, were identified in The Danish Attainment Register. Logistic and Poisson regression were used to estimate odds ratios (ORs) and mortality rate ratios (MRRs). RESULTS: OR of HIV diagnosis was 1.7 (95% confidence interval, CI 1.3-2.3) among heterosexual individuals with low educational attainments, but no associations between educational attainment and time to HAART initiation, CD4 cell count, or viral suppression were identified. All-cause MRRs were 1.8 (95% CI 1.0-3.2) and 1.8 (1.1-2.8) for HIV-infected patients and population controls with low educational attainment compared with medium and high educational attainment. MRRs for smoking and alcohol-related deaths were 3.6 (95% CI 1.5-8.9) for HIV-infected patients and 2.0 (95% CI 1.2-3.4) for population controls with low educational attainment compared with medium and high educational attainment. CONCLUSION: With free and equal access to healthcare, low educational attainment might increase risk of HIV infection among heterosexual individuals, but was not associated with late/very late presentation of HIV, time to HAART initiation, or HAART response. However, low educational attainment substantially increased lifestyle-related mortality, which indicates that increased mortality in HIV-infected patients with low educational attainments stems from risk factors unrelated to HIV.