Background:Autonomic disturbance can leads to blood flow changes that can be studied by various methods. Objective: To assess the blood flow changes in patients with severe carpal tunnel syndrome by laser Doppler flowmetry Methods:Ten patients with severe unilateral carpal tunnel syndrome confirmed by electrodiagnostic examination enrolled in this study. Patients comprised one man and nine women with mean age of 37 years, an average duration of symptoms for 29 weeks.Unaffected hand and little finger of affected hand were used as control. Skin blood flow was measured in neutral, flexed and extended positions of hands. Results: There was significant reduction of skin blood flow of median nerve territory as compared to control (unaffected hand) (p<0.05). There was also significant (p<0.05) reduction of blood flow of median nerve territory as compare to ulnar nerve territory of affected hand except in extended position. Conclusion: Circulatory disturbances are seen in hand skin of CTS patients. This change depends on the type and severity of CTS. This study showed a reduction of skin blood flow in severe form of CTS.