Staging laparotomy was performed as part of the routine recommended diagnostic evaluation following clinical staging (CS) in 692 patients presenting with supradiaphragmatic Hodgkin's disease (HD). Various clinical factors were analyzed by multivariate analysis for prediction of abdominal involvement. Factors that were statistically significant for predicting disease below the diaphragm included CS III-IV disease (P less than .001), B symptoms (P less than .001), mixed cellularity (MC) or lymphocytic depletion (LD) histology (P = .017), number of supradiaphragmatic sites greater than or equal to 2 (P = .001), male sex (P = 0.034) and age greater than or equal to 40 years (P = .004). Separate analyses were performed for various subgroups of CS IA-IIA, CS IB-IIB, CS IIIA-IVA, and CS IIIB-IVB patients. Upstaging was seen in 0% to 55% of CS I-II patients based on subgroup. Male sex, B symptoms, and number of sites above the diaphragm greater than or equal to 2 all independently predicted for positive surgical staging in CS I-II patients. Sixty-four percent of CS I-II patients who were upstaged had extensive abdominal disease by positive lower abdominal nodes or multiple splenic nodules (greater than or equal to 5). Downstaging (to pathological stage [PS] I-II) was seen in 9% to 68% of patients with CS III-IV disease based on subgrouping. Age greater than or equal to 40, MC or LD histology, and B symptoms all independently predicted for positive surgical staging in CS III-IV patients. Downstaging was more frequently seen in CS IIIA-IVA patients (55%) than in patients who were CS III-IVB (22%). Four subgroups of patients who had a low probability (less than 10%) of stage or treatment change following laparotomy were identified. These included CS IA female patients, CS IA male patients with lymphocyte predominance histology or high neck presentations, and patients with CS IIIB-IVB disease and account for 21% of the study population. Staging laparotomy altered the stage and treatment of a significant number of the remaining 79% patients and should continue to be recommended for this group of patients.