Deep vein thrombosis (DVT) is a risk factor for patients with acute stroke. Subclinical DVT is more common than clinically apparent DVT. DVT manifests with lower extremity swelling that might be associated with pain. Venous duplex ultrasound is a simple diagnostic procedure for detection of a DVT. However, as many as 30% of patients with acute pulmonary embolism show no evidence of lower extremity DVT, and thus a negative venous duplex ultrasound does not exclude the diagnosis of acute pulmonary embolism. Data suggest that heparin, of any type, may reduce the risk of venous thromboembolism in neurosurgical patients. One trial has shown that mechanical devices, such as intermittent pneumatic compression, significantly decrease the occurrence of asymptomatic DVT for patients with intracerebral hemorrhage as compared with elastic stockings alone, although this advantage was not found in a meta-analysis of prospective studies. Limitations in DVT prophylaxis raise a question about the need for more aggressive DVT surveillance.