As policymakers consider expanding insurance coverage for the human immunodeficiency virus (HIV+) population, it is useful to ask whether insurance has any effect on health outcomes, and, if so, whether public insurance is as efficacious as private insurance in preventing premature death. Using data from a nationally representative cohort of HIV-infected persons receiving regular medical care, we estimate the impact of different types of insurance on mortality in this population. Our main findings are that (1) ignoring observed and unobserved health status misleads one to conclude that insurance may not be protective for HIV patients, (2) after accounting for observed and unobserved heterogeneity, insurance does protect against premature death, and (3) private insurance is more effective than public insurance. The better performance of private insurance can be explained in part by more restrictive Medicaid prescription drug policies that limit access to highly efficacious treatment.