Background:Obesity rate among ladies have been growing, and it is one of the risk factors of surgical site infection (SSI) ensuing Caesarean delivery. Medical comorbidities, structural variables (such as increased tissue pressure and skin folds), and bioactive adipose tissue that are linked to an increase in the risk of SSI are all connected with obesity. In order to avoid SSI in obese women having caesarean deliveries, the work compares the effectiveness of cephalexin + metronidazole versus cephalexin alone. Objective: This study aimed to compare the effectiveness of cephalexin combined with metronidazole and cephalexin alone for SSI prevention in obese women having Caesarean deliveries. Subjects and methods: 280 patients participated in this interventional prospective randomised controlled-clinical trial in accordance with the inclusion and exclusion criteria. They were divided randomly in 2 groups (A & B), from them 270 patients completed follow up. In group A, patients received 2 gm cephalexin IV before skin incision then postoperatively they received 1 gm cephalexin IV after 8 hrs. In group B, patients received 2 gm cephalexin IV before skin incision plus 1 gm metronidazole rectally at time of urinary catheter insertion then postoperatively they received 1 gm cephalexin IV plus 1 gm metronidazole rectally after 8 hrs. Both groups were followed for the occurrence of SSI, endometritis, UTI, febrile morbidities, hospital stay and readmission and studied drugs side effects. Results: This study found a statistically significant difference in post-operative SSI rates (P>0.05). The most frequent postpartum complication in both groups was wound infection, which occurred more frequently in group A (the control group) than group B (the study group), with a statistically significant difference between the two. Between the two groups, there was no discernible difference in any other aspect of the postpartum experience for mothers.  The women in both groups did not significantly differ from one another concerning hospital readmission, receiving therapeutic antibiotic.  Concerning hospital readmission: in group A, 2 patients was readmitted to manage wound infection (wound dehiscence) and in group B no one was readmitted at hospital. As regards etiology of therapeutic antibiotic, it was mainly to manage wound complications according to C & S. Conclusion: Administration of prophylactic combined antibiotics to obese women prior to caesarean delivery was more effective than single antibiotic administration (cephalexin alone) in reducing post-CS SSI in class I obesity.