About one-third of all patients with the acquired immunodeficiency syndrome (AIDS) have Kaposi's sarcoma. Gastrointestinal involvement has been noted in 50% of homosexual men with cutaneous Kaposi's sarcoma and AIDS. We report the abnormalities on barium studies of nine homosexual men from the San Francisco bay area who have AIDS and documented gastrointestinal Kaposi's sarcoma. Submucosal nodularity and infiltrative irregularity were the most frequently noted findings and were demonstrated in the stomach, duodenum, small bowel, and colon. The duodenum was the most frequent site of abnormality. Coalescent plaques, some with umbilications, were seen in the colon. Although nonspecific, these radiographic abnormalities are highly suspicious for Kaposi's sarcoma, particularly in patients with or at high risk for AIDS, especially homosexual men.