A fifty-four-year-old woman died from multiple brain infarction and hemorrhage in the bilateral cerebrum, cerebellum, and brainstem, with renal infarction. She developed hematuria and transient blindness sixteen days before admission. Low-grade fever, heart murmur, and aortic valve vegetation on ultrasonic cardiography suggested infectious endocarditis. Autopsy study revealed occult adenocarcinoma in the lung and nonbacterial thrombotic endocarditis, but infective endocarditis was not histologically confirmed. The patient was considered to be a rare case of nonbacterial thrombotic endocarditis who developed multiple small infarctions mainly in the brainstem and cerebellum. Nonbacterial thrombotic endocarditis seems to be still an important disease as the embolic source, even if cryptic, of systemic thromboembolism.