We determined the immunogenicity and safety of reimmunization with the 23-valent polysaccharide pneumococcal vaccine in patients infected with human immunodeficiency virus type 1 (HIV-1). Patients immunized >5 years earlier (initially within 1 year of HIV-1 seroconversion) were randomized to receive vaccine (n=57) or placebo (n=30). Persons with recent HIV-1 seroconversion (n=14) were immunized for the first time. Preimmunization levels of capsule-specific immunoglobulin G were similar in all groups. Reimmunized patients showed a significantly lower frequency and magnitude of antibody responses compared with persons with recent HIV-1 seroconversion. Reimmunized patients did not show adverse virologic or immunologic changes, but some reported local discomfort (15%) or fever (8%). Thus, the limited responses after reimmunization of HIV-1-infected patients with the current 23-valent vaccine mandates the need for a more effective reimmunization schedule, more immunogenic vaccines, or other behavioral and therapeutic interventions.