Stroke in the cancer patient is most often caused by disorders of coagulation that are induced by the cancer, by cancer metastatic to the central nervous system, or by coagulation disorders or vascular injury induced by cancer therapy. Nonbacterial thrombotic endocarditis with diffuse thrombosis of cerebral vessels is often the cause of cerebral infarction. Venous occlusion is most common in leukemic patients but can also result from growth of solid tumor in the adjacent skull or dura. Chemotherapy administration is associated with a small risk of cerebral arterial or venous thrombosis. Radiation that is administered to the neck can result in delayed carotid atherosclerosis. Tumor embolization to the brain is a rare cause of stroke. Fungal septic cerebral emboli occur most commonly in leukemic patients who have undergone bone marrow transplant. Hemorrhages occur in the brain parenchyma or subdural space and are most commonly caused by acute disseminated intravascular coagulation or metastatic tumor. Hemolysis from chemotherapy administration is a rare cause of brain hemorrhage. Neuroimaging studies, measurement of coagulation function, and echocardiography are the must useful modalities to identify the cause of stroke.