This study was conducted to clarify the prevalence of venous thromboembolism (VTE) in neurosurgical patients. Prospective study for venous thromboembolism screening after neurosurgery was conducted. Thirty-seven patients were screened by ultrasonography for deep vein thrombosis in the lower extremities at an average of 12 days postoperatively. All patients received standard thromboprophylaxis using graded compression stocking with/without intermittent pneumatic compression following the VTE prevention guidelines. Definitive diagnosis of venous thromboembolism was made by contrast-enhanced whole-body computed tomography. Prevalence of deep vein thrombosis of the lower legs was 13.5% (5/37). Incidence of pulmonary embolism was 60% (3/5) in patients having deep vein thrombosis. All patients having venous thromboembolism were asymptomatic. In high-risk patients, VTE prevalence after neurosurgery was high even under mechanical prophylaxis. Additional pharmacological prophylaxis should be considered for patients with high risk of VTE.