Abstract: OBJECTIVE To investigate the prophylactic of antibiotics in preoperative period in our hospital and evaluate the reasonability of antibiotics usage. METHODS A total of 350 inpatients undergoing gynecologic and obstetric operation were randomly selected from May 1, 2009 to April 30, 2010. The preoperative prophylactic use of antimicrobial agents was investigated and analyzed. RESULTS ①Prophylactic antimicrobial agents were used in 350 cases(100%). ②The antimicrobial drugs included cephalosporin(70.22%), nitroimidazole(18.16%), fosfomycin (7.26%) and quinolones (2.42%). ③The average durations of antibiotic use were (3.05±2.02) d. ④100% of the patients received antibiotics within 2 h before operation. CONCLUSION Either the dosage or selection of antibiotic on the whole is reasonable in our hospital. Unreasonable use of preoperative prophylactic antimicrobial agents is common, especially for type I incision, and must be made further standardization.