A 48-year-old woman underwent total gastrectomy, splenectomy, and distal pancreatectomy with en bloc regional lymph node dissection for gastric carcinoma. Dull pain in the right upper quadrant and the back developed postoperatively. Contrast-enhanced computed tomography and ultrasonography disclosed portal vein thrombosis (PVT). Heparin and urokinase were given in conjunction with antibiotics. This treatment resulted in clinical improvement, but failed to achieve complete thrombolysis. Cavernous transformation of the portal system was confirmed. Although PVT after splenectomy has been reported mainly in patients with hematological disorders, our case suggests that splenectomy for en bloc node dissection in gastric carcinoma is a possible cause of PVT.