Background: Limb immobilization is one of treatments for managing musculoskeletal injury. Although immobilization often benefit the affected part of the body, when prolonged, it often harms the rest of body. Objective: Studying the morphological and functional changes in the nerves of immobilized muscles. Materials and Methods: Thirty four adult male albino rats weighing from 140 –160 g were included in the study. The rats were classified into two  equal groups: control group included rats not exposed to immobilization, and experimental group included rats exposed to immobilization. After 14 days of immobilization, the rats were sacrificed and the sciatic nerve was dissected and placed in moist nerve chamber, then stimulated by power lab 4/25 stimulator for measuring the nerve conduction velocity (NCV), and the amplitude of action potential. Results: Immobilized group showed a significant decrease in both the NCV, and amplitude of action potential of sciatic nerve in comparison to the control group. In addition, there were  histological findings suggesting degeneration of myelin sheath and nerve axons. Conclusion: Limb immobilization altered the physiological parameters and histological characters of sciatic nerve.