Introduction:-Nerve conduction study is the most sensitive test for diagnosis of carpal tunnel syndrome. This test could be normal in some patients with mild (CTS), as sensitivity is 82-85%. Median nerve conduction study evaluation after provocative tests (e.g. modified phalen`s test, hand elevation and wrist radial traction) may be helpful for diagnosis of mild CTS. Objective: - To study the effect of clinical provocative tests and electrodiagnostic studies for diagnosis of mild clinical carpal tunnel syndrome, and to determine the sensitivity and specificity of provocative tests for diagnosing carpal tunnel syndrome. Material and method: - The study was conducted on 30 patients (15 patients with clinical carpal tunnel syndrome and normal routine electrodiagnosis test results and 15 patients with clinical mild carpal tunnel syndrome) compared to 10 healthy subjects with measuring the combined sensory index (CSI) before and after provocative tests. Result: Post provocative CSI showed higher statistical significant index than pre provocative CSI in all our patients groups and higher diagnostic value. Okutsu`s test showed the highest sensitivity and specificity in our patients groups. Conclusion: For diagnosis of patients with probable mild CTS, CSI after provocative test which one study could be suggested to increase the accuracy of the diagnosis.