A total of 10 cases of non-bacterial thrombotic endocarditis (NBTE) were found among 1640 adult patients, autopsied in a 24-year period. Eight out of 10 patients had an underlying malignant tumor, NBTE was more common in cancer patients than in patients without malignancy (1.25% vs 0.2%, P less than 0.05). Patients with adenocarcinoma were at higher risk than patients with other malignant processes (2.70% vs 0.47%, P less than 0.05); especially in cases of pancreatic cancer in comparison with other kinds of adenocarcinoma (10.34% vs 1.55%, P less than 0.05). Systemic embolization was the main cause of morbidity. Any thromboembolic event in cancer patients should prompt a search for NBTE. NBTE may be present in undisseminated cancers in otherwise curable patients.