Hepatic venous outflow obstruction caused by hepatic vein thrombosis (HVT) is a manifestation of a hypercoagulable state, most commonly a myeloproliferative disorder (MPD). In the past, HVT was thought to have a poor prognosis unless treated surgically with portosystemic shunt or orthotopic liver transplantation (OLT). The aim of this study was to assess whether early diagnosis of the underlying hematologic disorder and institution of appropriate medical therapy have altered outcome. We reviewed the charts of 22 patients with HVT evaluated at our center from January 1986 to January 1995. The median age was 32 years (range, 14 to 59 years). Underlying etiologies were MPD, 13 (polycythemia vera, 8; essential thrombocythemia, 4; undefined, 1); dysfibrinogenemia, 1; anticardiolipin antibody, 1; oral contraceptive use, 3; and idiopathic, 4. All patients had ascites, hepatomegaly, and/or abdominal pain. Two underwent mesocaval shunting, and 1 had a peritoneal-venous shunt. Seven patients, including 1 with a mesocaval shunt, underwent OLT. The median duration of symptoms before transplantation was 6 months (range, 1.5 to 11 months). Six transplant patients are alive on long-term anticoagulation therapy at a mean post-OLT follow-up of 42 months (range, 2 to 77 months), without recurrence. Of 13 patients treated medically, 10 (77%) are alive at a median follow-up of 40 months (range, 17 months to 14 years 8 months), 1 has died, and 2 have been lost to follow-up. In a majority of patients, symptoms improve with prompt treatment of the underlying hematologic disorder, with a favorable long-term prognosis. Patients with decompensated liver disease can successfully undergo OLT with a low risk of recurrence on long-term oral anticoagulation.