Findings from histologic analysis, lymphangiography, ultrasonography, and computed tomography were reviewed for 54 cases of Hodgkin's disease and 18 cases of non-Hodgkin's lymphoma. All patients were classified as clinical stage 1 or 2 disease at the time of the imaging studies. The ultrasound and computed tomography studies identified only 30 to 40% of the truly positive patients. This low sensitivity contrasts with lymphangiography, which identified 95% of the truly positive Hodgkin's disease patients and 70% of the patients with abdominal spread of non-Hodgkin's lymphoma. Many errors in interpretation were attributable to location and distribution of disease in these patients and the differing patterns of spread in Hodgkin's disease and non-Hodgkin's lymphoma. The evidence indicates that when findings are positive on computed tomography or ultrasound, no other study is necessary. In stage 1 or 2 lymphoma, non-Hodgkin's patients with negative noninvasive findings and all Hodgkin's patients, regardless of their noninvasive findings, should undergo lymphangiography.