Background: Carpal tunnel syndrome (CTS) is one of the most diagnosed disabling conditions of the upper extremities. Corticosteroid local injection is one of the traditional treatments. Platelet-Rich Plasma (PRP) local injection has emerged as a new treatment, promoting nerve regeneration. Objectives: Comparison of the effectiveness of a single PRP local injection to a single corticosteroid local injection for treating idiopathic CTS using nerve conduction studies and Visual Analog Scale.  Patients and method: 40 patients with mild idiopathic CTS were diagnosed clinically and selected according to Padua's Neurophysiologic Severity Scale (PNSS) started the study. They were divided into 2 equal groups; the first group of patients received a single local corticosteroid injection, and the second group received a single local PRP injection. Nerve conduction studies (NCS) in the form of median nerve sensory conduction velocity and the Visual Analogue Scale (VAS) were compared in both groups before and three months after injection.  Results: Our study included40 patients randomly grouped into two equal main categories. Group I (corticosteroid group) included 20 patients with a mean age of 41.50±11.26 years, while Group II (PRP group) included 20 patients with a mean age of 39.10±11.24 years. VAS and median nerve sensory conduction velocity were significantly reduced in group II compared to group I. Conclusions: PRP single local injection in the wrist proved to be better than corticosteroids single local injection for managing mild idiopathic CTS.