Switching from heparin to acenocoumarol was complicated by severe retroperitoneal bleeding in a 50-years old patient with massive pulmonary embolism and deep venous thrombosis. The haematomas were evacuated by surgical procedure. Planned insertion of a vena cava filter was abandoned because of a mobile clot in inferior vena cava (IVC) reaching above renal veins as evidenced by spiral computed tomography (SCT). Patient was transferred to the Surgical Department of Medical Academy in Warsaw where thrombectomy was performed. In spite of mechanical and pharmacological methods of venous thrombosis prophylactic, thrombectomy was complicated by massive proximal deep venous thrombosis of right leg and distal part of IVC. Patient was successfully treated with UFH i.v. followed by low molecular weight heparins. No bleeding complications were observed. Screening for thrombophilia and cancer were negative. This case report is an example of difficulties in clinical management in a patient who has both life-threatening thromboembolic disease and bleeding.