Histoplasmosis is the most common endemic mycosis in individuals with AIDS, occurring in 2%-5% of this population. Infection is more likely to be disseminated than in immunocompetent individuals and generally presents insidiously with nonspecific symptoms. The gastrointestinal tract is involved in 70%-90% of cases of disseminated histoplasmosis, yet gastrointestinal histoplasmosis per se is infrequently encountered in patients with AIDS. The diagnosis of gastrointestinal histoplasmosis is often not suspected, particularly in areas of nonendemicity, and a delay in diagnosis may lead to increased morbidity and risk of death. Since antifungal therapy improves outcome for >80% of AIDS patients with histoplasmosis, it is essential that caregivers be aware of the varied presentations of gastrointestinal histoplasmosis in order to diagnose and to treat this potentially life-threatening infection effectively.