Two patients developed superior vena cava syndrome following total parenteral nutrition through a central venous catheter. Infection may have contributed to the development of the superior vena cava thromboses. In one patient a "sleeve thrombus" probably caused multiple pulmonary embolisms after the catheter was withdrawn. The other patient had a mural thrombosis with complete occlusion of the superior vena cava. The author emphasizes the importance of early diagnosis and correct treatment in order to reduce the high mortality rate due to this serious complication to central venous catheters.