We reviewed the charts of the cancer patients admitted in a medical oncology ICU during an 11-month period. Among 330 admissions (55% for a medical complication, 45% for monitoring during administration of an intensive or potentially toxic treatment), 49 patients died and 34 autopsies were performed. Every autopsied case was reviewed by a group of oncologists and pathologists. The direct cause of death was neoplasia itself in only four patients. Six deaths remained unexplained after post mortem examination. In 23.5% of cases, the direct cause of death was a major infection (four aspergillosis, two candidemia, one CMV pneumonia, one acute cholecystitis). Overall, the clinical diagnosis of the immediate cause of death was correct in only 41% of the cases. Lesions of pulmonary edema (PE) were found at autopsy in 68% of the cases. No predictive factors for PE were determined.