Surgical site infection (SSI) is defined as a proliferation of pathogenic microorganisms which develops in an incision site either within the skin and subcutaneous fat (superficial) and musculofascial layers (deep) or in an organ or cavity, if opened during surgery. SSIs account for 20% to 25% of all hospital acquired infections worldwide. The rate of HAIsis markedly higher in many developing countries. The present study aimed at obtaining the incidence of SSI and to evaluate the risk factors as well as to formulate an antibiotic policy for patients posted for any surgery in Tirunelveli medical college hospital. To determine the rate of surgical site infection among patients admitted in Intensive surgical care unit and post surgical ward in a tertiary care hospital.2. To isolate the pathogens and find the antibiotic susceptibility pattern. The Study Population and Size is 50. The Study Period is March 2017 to August 2017. Department of Microbiology. The Study Sample was collected from patients who developed SSI. Two wound swabs were collected aseptically a. Gram stain microscopy using first swab.b. Inoculation on culture media using second swab c. Identification of the isolates by standard biochemical test. d. Antimicrobial susceptibility testing by Kirby Bauer disk diffusion method. Ethical clearance from institutional ethics committee Tirunelveli medical college. Surveillance for SSIs in each centre will determine the rate of SSIs, distribution of micro organism and antimicrobial susceptibility pattern of the isolates. Empirical treatment of the SSIs can be made using these relevant data which will ensure reduced patient stay, morbidity, cost per day in the hospital.