Vascular complications associated with antineoplastic agents are being reported with increasing frequency. Such vascular toxicity is clinically heterogeneous, ranging from asymptomatic arterial lesions to a fatal thrombotic microangiopathic syndrome. Mitomycin is most commonly implicated in the thrombotic microangiopathic syndrome, while bleomycin, either alone or in combination with a vinca alkaloid or cisplatin, appears to be an important cause of Raynaud's phenomenon. Acute arterial ischemic events, ie, myocardial infarction and cerebrovascular accidents, occur most frequently after cisplatin-based combination chemotherapy. Putative mechanisms for such toxicity include drug-induced endovascular damage, perturbation of the clotting system, platelet activation, an abnormality of thromboxane-prostacyclin homeostasis, autonomic dysfunction, vasculitis, and stimulation of fibroblasts. More than one mechanism may be operative in an individual patient. Better documentation of the incidence and types of vascular toxicity and studies to help elucidate the pathogenesis and management of such toxicity are needed.