Marmara Üniversitesi Eczacılık Fakültesi, Klinik Eczacılık Bilim Dalı, İstanbul, Türkiye DOI : 10.12991/201115434 Our study was performed in a teaching and research hospital in Istanbul between the dates 01.10.2009- 31.12.2009 with the aim of evaluating the use of surgical prophylaxis. Preoperative antibiotic prophylaxis (PAP) administered to 406 patients operated during the study was evaluated in terms of age, gender, selection of patient and antibiotics, wound classification, duration of hospital stay, American Society of Anesthesiologists (ASA) score, presence of diabetes, hepatic and renal insufficiency and history of allergy. The patients were classified as emergent or elective according to their state of being. Only by taking elective surgical operations into consideration, evaluation was done through surgical prophylaxis guideline that was prepared by the hospital infection committee. It was seen that the most frequently used antibiotic in PAP is cefazolin. PAP use was found to be compatible with the local guideline in 211 elective cases (51.97%). In 126 patients (31.03%), prophylaxis time was longer than that was recommended in the guideline. In 10 (2.46%) patients, selections of antibiotics were different from the guideline. Unnecessary antibiotic prophylaxis in the absence of risk factors and different dose of antibiotic were observed in 59 cases (14.5%). It is well known that the inappropriate surgical prophylaxis can cause irrational antibiotic use and economic burden. In order to increase the quality of PAP applications, medical staff should be informed via educations by a multi-disciplinary group including clinical pharmacists who have competence in pharmacodynamic and pharmacokinetic characteristics of medications and rational drug use. Hospitals must prepare and regularly update their own PAP guides according to the evidence based literature. Keywords : Surgery, prophylaxis, antibiotic, clinical pharmacist, cefazoline