Because of the spleen's extensive collateral circulation, the risk of splenic infarction after splenorenal arterial bypass (SRB) has been considered negligible. We report four patients in whom splenic infarctions developed after SRB. Splenic infarction developed in one patient at the time of SRB, and symptoms of splenic abscess (fever, abdominal pain, and leukocytosis) that proved to be splenic infarctions at laparotomy developed in three patients 2 to 16 days after the operation. Factors possibly contributing to splenic infarction could be determined for three patients. These included interruption of collateral vessels, intraoperative hypotension and disseminated intravascular coagulation, and distal splenic artery ligation. Normal Doppler flow was detected in the splenic parenchyma during test occlusions of the splenic artery before SRB in three patients. Our experience suggests that existing collateral circulation may not always sustain splenic viability after SRB, and some patients may not be suitable candidates for this operation. Factors such as adequacy of inflow, splenic artery length, and risk of perioperative hypotension should be considered.