Saccharomyces cerevisiae is a yeast that is more commonly known as brewer’s yeast. Commercial uses include beer and wine production, health food supplementation, and, more recently, hepatitis B vaccine production by recombinant DNA techniques. Occasionally, S cerevisiae has been isolated from clinical specimens and rarely has been a cause of serious infection. Case reports are few, and S cerevisiae has frequently been isolated in association with more common pathogenic organisms. We describe a case of S cerevisiae septicemia in association with acquired immunodeficiency syndrome (AIDS).