Objective: To investigate the effects of neuromuscular electric stimulation (NMES) on endothelial vascular control and hemodynamic function in patients in rehabilitation after acute stroke. Design: Before- after trial. Setting: Inpatients in a tertiary hospital. Participants: Sixteen stroke patients (11 women, 5 men) with a mean age of 60.6 +/ - 19. 5 years. Interventions: All patients received NMES for paretic wrist extensor and flexor muscles 30 minutes daily, 5 days a week, for 4 weeks. The nonparetic upper extremities , which served as controls, did not receive NMES. Main Outcome Measures: Laser Doppler perfusion testing was conducted to measure cutaneous microcirculatory reponses to transdermal iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP), as specific endothelium-dependent and - independent vasodilators, respectively. Arterial and venous hemodynamic function was also measured by impedance plethysmography. Results: Before NMES treatment, the venous capacity and compliance of the paretic extremities did not differ significantly from those of the nonparetic extremities. However, hyperemic arterial inflow, ACh-induced cutaneous perfusion, and the ratio of ACh- to SNP-induced cutaneous perfusion were lower in the paretic than in the nonparetic extremities. After NMES treatment, hyperemic arterial inflow and venous outflow increased by 21.5% and 57 .2%, respectively, in the paretic extremities (P