We evaluated the association of HIV infection and immunodeficiency with acute coronary syndrome (ACS) recurrence, and with all-cause mortality as a secondary outcome, after hospitalization for ACS among HIV-infected and HIV-uninfected individuals. We conducted a retrospective cohort study within Kaiser Permanente Northern California of HIV-infected and HIV-uninfected adults discharged after ACS hospitalization [types: ST-elevation myocardial infarction (STEMI), non-STEMI, or unstable angina] during 1996-2010. We compared the outcomes of ACS recurrence and all-cause mortality within 3 years, both overall by HIV status and stratified by recent CD4 count, with HIV-uninfected individuals as the reference group. Hazard ratios (HRs) were obtained from Cox regression models with adjustment for age, sex, race/ethnicity, year, ACS type, smoking, and cardiovascular risk factors. Among 226 HIV-infected and 86 321 HIV-uninfected individuals with ACS, HIV-infected individuals had a similar risk of ACS recurrence compared with HIV-uninfected individuals [HR 1.08; 95% confidence interval (CI) 0.76-1.54]. HIV infection was independently associated with all-cause mortality after ACS hospitalization overall (HR 2.52; 95% CI 1.81-3.52). In CD4-stratified models, post-ACS mortality was higher for HIV-infected individuals with CD4 counts of 201-499 cells/?L (HR 2.64; 95% CI 1.66-4.20) and < 200 cells/?L (HR 5.41; 95% CI 3.14-9.34), but not those with CD4 counts ? 500 cells/?L (HR 0.67; 95% CI 0.22-2.08), compared with HIV-uninfected individuals (P trend < 0.001). HIV infection and immunodeficiency were not associated with recurrence of ACS after hospitalization. All-cause mortality was higher among HIV-infected compared with HIV-uninfected individuals, but there was no excess mortality risk among HIV-infected individuals with high CD4 counts.