Till December 31st 1976, diagnostic laparotomy was carried out in 58 patients with Hodgkin's disease. Of these, 23 cases (40%) revealed abdominal involvement. The tumor stage found by conventional diagnostics before surgical treatment had to be altered in 16 patients (27%). It had to be increased in ten and lowered in six cases. Of 13 splenic Hodgkin infiltrations twelve had not been supposed preoperatively; four out of 43 sound organs had been suspected preoperatively because of splenomegaly. Subdiaphragmatic histological findings involving a rather unfavorable prognosis were seen in nine patients (16%). In Hodgkin's disease, risk groups cannot be selected with confidence, as no definite correlation between the frequency of subdiaphragmatic affection and the primary manifestations, histology or general symptoms was observed. Since operation risk of diagnostic laparotomy is low, operable stage I-III cases with Hodgkin's disease should undergo diagnostic laparotomy prior to treatment planning.