One hundred and fifty consecutive splenectomies, performed at the Royal Prince Alfred Hospital over a five-year period beginning in 1968, have been reviewed in a retrospective study. Splenectomy incidental to some other resectional procedure in the upper abdomen carried a mortality of 17%, accidental injury to the spleen during upper abdominal surgery carried a mortality of 28%, external trauma to the spleen a 7% mortality, while splenectomy for the diagnosis or therapy of a haematological disorder carried the lowest mortality, namely 4%. Morbidity and mortality were related to the age of the patient, and the mortality among patients 60 years or more was 26%. Pulmonary complications (excluding pulmonary embolus) occurred in 48% of patients. Clinically evident thromboembolism was detected in 10.7% of patients. A definite relationship to platelet counts of more than 500,000/mm3 was noted amongst patients who were not heparinized. Splenectomy is associated with a high morbidity and a significant mortality. Surgeons performing the operation and physicians referring patients for splenectomy need to be aware of the risks involved. Careful patient selection, scrupulous perioperative management, and meticulous surgery may reduce both morbidity and mortality. Elective splenectomy should be managed by a team of surgeons and physicians with a specific interest in the problems involved.