The safety and immunogenicity of inactivated hepatitis A (HepA) vaccine was assessed in 133 hepatitis A virus-seronegative, human immunodeficiency virus (HIV)-infected adults. Patients were randomly assigned to receive, in a blinded fashion, either 2 doses of vaccine (1440 enzyme-linked immunosorbent assay units) or placebo 6 months apart. Seroconversion at month 9 was observed in 68% of those with CD4 cell counts >/=200 cells/mm(3) but in only 9% of those with lower CD4 cell counts (P=.004). HepA vaccine was well tolerated and had no effect on the course of HIV infection or plasma HIV RNA load.