Background: Incisional hernia is a common surgical condition with a reported incidence of 2-11% of patients subjected to abdominal operations. Aim: This is a prospective study to compare the differences in the post-operative events of the onlay mesh repair and the sublay mesh repair in our setup. Methods: This is a prospective study of 60 cases of incisional hernia that were operated in the department of general surgery, Govt. medical college, Omandurar govt. estate, Chennai, India from Dec 2017 to June 2018. Patient’s history, clinical findings, investigations, operative findings, operative procedures and  postoperative complications were all recorded in a proforma specially prepared. All patients underwent open mesh repair. Randomsation was done, as every other case was alternately proceeded with onlay and sublay mesh placement. Patients were followed up for immediate post-operative complications. The two groups were compared using appropriate statistical tests. Results: Most of the patients presented with incisional hernia in the infraumbilical region. Both the groups had 30 patients each. Operative time and pain score was significantly higher in the sublay group; whereas the drainage volume and duration and the incidences of seroma, superficial surgical site infection and flap necrosis were higher in the onlay
group. Conclusion: Even though, the operative time and the pain score were significantly higher in the   sublay group, theoretically, it is considered as a superior technique of mesh placement. The study showed that the post-operative complications were higher in the onlay group. 

Keywords: Incisional Hernia; Onlay Mesh Repair; Sublay Mesh Repair; Post-Operative Complications.