On review of 63 barium sulfate examinations in 44 patients with acquired immunodeficiency syndrome (AIDS), 61% of the 23 single-contrast examinations and 98% of the 40 double-contrast examinations were abnormal. Abnormalities involved all areas of the gastrointestinal (GI) tract and covered a wide spectrum of findings including thickened folds, nodularity, increased secretions, superficial erosions, ulcerations, plaque formation, and tumor mass. Abnormalities, when present, were most commonly multifocal (three or more sites) on upper GI study (64%) and barium enema (69%). Thirty-eight patients (86%) had at least one abnormal study; 27 of these patients had multifocal disease in either the upper or lower tract separately or combined. The most common site of abnormality was the duodenum on upper GI study and the sigmoid colon on barium enema. In 27 cases the radiographic abnormalities could be specifically correlated with a malignancy or an opportunistic infection by endoscopy, colonoscopy, culture, biopsy, or autopsy. Multifocal disease of the upper and/or lower GI tract, especially when the duodenum is involved, should suggest AIDS even in patients not thought to be at high risk for the disease.