Background: Component separation technique is an ideal method to repair large incisional hernia with wide fascial gap, as it allows sliding of the abdominal wall layers giving length to close the abdomen after return abdominal contents without tension and return of midline linea alba. Objective: To compare between component separation technique with or without mesh repair in the treatment of large incisional hernia. Patients and Methods: The current study included 40 patients with large midline incisional hernia had repaired the hernia by component separation technique at the Department of Surgery, Al-Azhar University Hospitals during the period from November 2018 to October 2020.The patients were divided into two equal groups: Group A had component separation technique with mesh, while group B had component separation technique without mesh. Results: There were significant increase inseroma and post-operative infection in group B (35% and 25% respectively) than patients in group A (15% and 10% respectively). Chronic pain significantly increased in group A patients (25%) than group B (10%).Recurrence significantly increased in group B patients (40%) than group A patients (10%). Conclusion: Post-operative hernia recurrence, wound seroma and infection in group B patients were higher than group A, but chronic pain is higher in group A.