Background: Carpal tunnel syndrome is a prevalent disease with significant morbidity. The current treatments range from oral medication and local corticosteroid injection to surgical carpal tunnel release (CTR). In this study, we tried to assess the results of Carpal Tunnel Release surgery in combination with the anti-inflammatory effect of local corticosteroid injection. Methods: 65 patients were enrolled by clinical and electrodiagnostic tests and randomly divided into two groups, 32 in group one which underwent surgery with Dexamethasone injection and 33 in group 2 which intervened with carpal tunnel release surgery alone. Data on Boston questionnaire of patients were conducted before and two weeks after surgery. Distal motor and sensory latencies of patients were recorded before and two months after surgery. Mean values were compared between groups before and after surgery. Results: The mean preoperative Boston index was 35.83 in group one and 37.7 in group two, these data postoperative were 15.83 and 19.15 respectively. The mean preoperative distal sensory latency was 54.8 in group one and 47.6 in group two, these data postoperative were 34.1 and 35.1 respectively. The mean preoperative distal motor latency was 63.2 in group one and 62.3 in group two, these data postoperative were 44.5 and 46.55 respectively. Conclusions: CTR surgery plus local corticosteroid injection did not significantly change in results of Electrodiagnostic test or Boston index compared to the non-injection group.