Hemostatic abnormalities are rather frequent in cancer patients either in hematological or in solid tumors. Acute disseminated intravascular coagulation (DIC) is a rare coagulopathy in cancer patients, but when it develops it becomes rapidly fatal. Between June 1988 and December 1992 we observed 8 cases of acute DIC occurring in gastric cancer (4 patients), breast cancer (3 patients) and high-grade non-Hodgkin lymphoma (1 patient). In 3 patients affected by gastric carcinoma, acute DIC was the first manifestation of the presence of the tumor, while in the other patients DIC occurred during the course of the disease. All the patients were treated with heparin, fresh frozen plasma and platelet support, but only in 1 patient was a short duration improvement of clinical conditions and coagulation tests recorded. Acute DIC can be the first manifestation of gastric tumors and the presence of the hemorrhagic syndrome associated with thrombocytopenia, hypofibrinogenemia and fibrin/fibrinogen degradation products should initiate a search for gastric carcinoma.