Two subjects with cerebral embolism were found at autopsy to have marantic (nonbacterial thrombotic) endocarditis (NBTE) and an unsuspected carcinoma. A additional 16 subjects with marantic endocarditis and cancer were found on reviewing the autopsy records of 22 subjects with NBTE. Of these 18 subjects with NBTE and cancer, eight developed a stroke during their illness, in five as the initial manifestation of cancer. Although the association of cancer and marantic endocarditis is generally well recognized, cerebral embolism from this source should be more seriously considered as one of the "remote effects" of cancer on the nervous system.