The frequency and distribution of gastrointestinal Kaposi's sarcoma were prospectively investigated in 33 consecutive AIDS patients with heterogeneous risk factors and established skin or lymph-node disease. The influence of visceral involvement and degree of immunosuppression at the time of diagnosis on patient survival was also evaluated. Gastrointestinal lesions were found in 17 cases (51%): 5 patients (15%) had both upper and lower GI tract involvement, 8 patients (24%) had only gastroduodenal lesions, and 4 (12%) only lower tract disease. No difference in the frequency of visceral involvement was found between the two major risk groups (homosexuals and intravenous drug abusers). The degree of immunosuppression at diagnosis was the major determinant of survival, whereas gastrointestinal involvement did not in itself significantly influence patient survival. Morbidity from enteric Kaposi's sarcoma was quite low, 80% of these lesions being clinically silent during the follow-up period.