The records of 816 cancer patients who had a complete postmortem examination during a 3-year period were reviewed. Death resulted from infection in 47% of the patients, from organ failure in 25%, and from infarction, hemorrhage, and carcinomatosis in 11%, 7%, and 10%, respectively. The most common fatal infections were pneumonia, septicemia, and peritonitis. The majority of infections were caused by gram-negative bacilli, mainly E. coli, Pseudomonas spp., and Klebsiella spp. In 71% of the 816 patients, the underlying tumor precipitated the cause of death. Consequently, better modalities of cancer therapy and supportive therapy are needed.