Background: the use of routine prophylactic antibiotics substantially reduces the rate of post cesarean section infection. Aim: to test the efficacy of 2 gram of cefatriaxone as single dose pre operatively as extended broad spectrum antibiotics in prophylaxis against post Cesarean section infection in elective operation in low socio economic society. Subjects and Methods: Our study is pilot clinical trial done in Hadhramout government in Yemen to detect the percentage of infection post Cesarean section after use of prophylactic dose of 2 gram of cefatriaxone as single dose pre operatively and relation of base line criteria and surgical character in this regime of prophylaxis. Results: One hundred women were involved in the study and received the prophylactic dose of cefatriaxone pre operatively half an hour to one hour before Cesarean section and base line character involving, age, BMI parity, number of previous Cesarean section, indication for Cesarean section, duration of surgery, type of anesthesia, details infection if occurred post Cesarean section, maternal side effect, and any neonatal complication. The percentage of infection after prophylactic dose was 4% and the risk factor was increase of BMI and repeat Cesarean section in 50% of cases without any maternal or neonatal side effects. Conclusion: Use of extended broad spectrum antibiotics was effective in decreasing soft tissue infection post elective Cesarean section and another study is needed to compare the use of different regime of broad extended spectrum in either elective or emergency operation.