Between 1 January 1980 and 31 July 1988, 62 patients with chronic lymphocytic leukaemia (CLL) or malignant non-Hodgkin's lymphoma (NHL) were splenectomized for splenomegaly and presumed hypersplenism. All patients except one had splenomegaly (mean (s.d.) weight 1585(872) g, range 150-4300 g) and 34 had massive splenomegaly (greater than 1500 g). Forty-nine patients had platelet counts less than 100 x 10(9)/l and 16 patients had anaemia with haemoglobin levels less than 10 g/dl. White cell counts were less than 3 x 10(9)/l in six NHL patients. Fifteen patients had bicytopenia, and three NHL patients had tricytopenia. The selected group of 62 patients underwent splenectomy largely because of failure to respond to medical therapy (39 patients) or inability to tolerate or start adequate chemotherapy because of very low blood counts (11 patients). There was one postoperative death, and a 29 per cent morbidity rate. The response rate was 89 per cent in the first month after splenectomy and 39 patients (63 per cent) had a continuing complete response with a median follow-up of 26 months (range 3-96 months). Twelve patients (10 with CLL) received no further therapy after splenectomy. Seven patients failed to respond and 15 relapsed after splenectomy. These 22 patients could be distinguished on the basis of: (1) lower average preoperative platelet counts (P less than 0.007), postoperative platelet counts (P less than 0.001), and postoperative rise in platelets (P less than 0.004); (2) lower average spleen weight (P less than 0.052); (3) preoperative chemotherapy (P less than 0.044). However preoperative and postoperative platelet counts were the only two variables selected by stepwise regression analysis (P less than 0.05 and P less than 0.01, respectively). Bone marrow failure did not preclude complete response after splenectomy. Long-term survivors emerged from the group of patients with continuing complete response. Of the seven patients who failed to respond, five died with a median survival of 4 months, and of the 15 patients who relapsed after splenectomy, 13 died, with a median survival of 6 months after relapse and 18 months after splenectomy. Thus, splenectomy may be an effective palliation for both CLL and NHL patients with splenomegaly and hypersplenism.