The results of staging in 170 patients with non-Hodgkin's lymphoma have been reviewed; all patients were subjected to a series of sequential procedures, including lymphangiography, bone marrow biopsy, and liver biopsy (performed percutaneously, by peritoneoscopy, or by laparotomy). A high incidence of involvement of bone marrow, liver, and abdominal nodes was found in patients with nodular types of lymphoma and in those with diffuse lymphocytic lymphoma, with less than or equal to 20% remaining in stage I or II at the completion of staging in each of these subgroups. Only in patients with histiocytic lymphoma was there an appreciable percentage (31%) remaining in the stage I-II categories after staging. In this study, 75 patients remained in stage III or less after completing the non-surgical phase of staging, and laparotomy was utilized in only 50 patients (30%). At laparotomy, involvement of the liver or the mesenteric or portal lymph nodes was found in 81% of patients with a positive lymphangiogram but in only 18% of those with a negative lymphangiogram.