Introduction: Surgical site infections (SSIs) are a common complication of abdominal surgery, and the optimal regimen and duration of antibiotic prophylaxis remain unclear. This study aimed to evaluate the efficacy of antibiotic prophylaxis in reducing SSIs in patients undergoing elective abdominal surgery. Methods: A prospective randomized trial was conducted in 98 adult patients undergoing elective abdominal surgery. Patients were randomized into the cefazolin prophylaxis group or the no prophylaxis group. Patients were followed up for at least 30 days postoperatively to monitor for the development of SSIs. Results: The incidence of SSIs was significantly lower in the antibiotic prophylaxis group (6.3%) compared to the no prophylaxis group (24.0%) (p=0.02). There were no significant differences in the rates of other postoperative complications between the two groups. Conclusion: This study provides evidence that a single preoperative dose of intravenous cefazolin is effective in reducing the incidence of SSIs in adult patients undergoing elective abdominal surgery. Further studies are needed to determine the optimal regimen and duration of prophylaxis in patients undergoing abdominal surgery.