Thrombohemorrhagic complications in chronic myeloproliferative disease(CMPD) including chronic myelogenous leukemia(CML) are not rare. Lower incidence of disordered hemostasis is reported in CML compared with other CMPD. The mechanism of thrombohemorrhagic complications might be a consequence of qualitative platelet abnormalites and prolonged bleeding time rather than that of thrombocytosis. Although defect of platelet function has been extensively investigated, there was no established consistent correlation between clinical bleeding and number and function of platelet. The most common site of bleeding complications in the CMPD is superficial mucosa. Bleeding in deep tissue and viscera is very unusual. We report a case of CML which developed a huge spontaneous retroperitoneal hematoma.