en Infectious Disease Infectious Disease Original Research Original Research <p> <strong> Background </strong>:The present study was conducted to establish the patterns and risk factors of surgical site infections in our institution between 2006 and 2011. </p><p> <strong> Methods: </strong>This was a retrospective cross-sectional study. The surgical site infection (SSI) was identified based on the presence of ICD-10-CM diagnostic code in hospital discharge records. By using a standardized data collection form predictor variables including patient characteristics, preoperative, intra-operative and postoperative data were obtained. </p><p> <strong> Results: </strong>Ninety five patients fulfilled the inclusion criteria. The patients were admitted for various procedures including both elective (62.1%) and emergency (37.9%) operations. Colectomy (13.7%) was the leading procedure followed by umbilical herniation (12.6) and appendix perforation (12.6%). The mean age was 47.13 years with standard deviation of 19.60 years. Twenty percent were addicted to opium. Midline incision above and below the umbilicus (40%) had the highest prevalence of infection. Most patients (46.3%) had clean-contaminated wounds and 30.5% had contaminated one. The quantitative variables which were also measured include duration of surgery, pre-operative and post-operative hospital stay with the mean of 2.9±1.45 hours, 1.02±1.42 and 7.75±6.75 days respectively.The most antibiotics prescribed post-operatively were the combination of ceftriaxone and metronidazole (51.6%). </p><p> <strong> Conclusion: </strong>The contaminated and clean-contaminated wounds are associated with higher rate of SSIs. Also, there was a converse relation between length of surgical incision and rate of SSIs. In overall, we found type of surgery as the main risk factor in developing the SSIs. </p> Risk factor, Surgical Wound Infection, Contamination, International Classification of Diseases. 319 323 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-682&slc_lang=en&sid=1 Mohammad Reza Motie motiem@mums.ac.ir 200319475328460012802 200319475328460012802 Yes Surgical Oncology Research Center, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Majid Ansari 200319475328460012803 200319475328460012803 No Oncology Research Center, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Hamid Reza Nasrollahi 200319475328460012804 200319475328460012804 No Surgical Oncology Research Center, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.