Antimicrobial prophylaxis is the periprocedural systemic administration of an antibiotic, used to reduce the risk of postprocedural local and systemic infections. The present retrospective study was done in 100 patients who had undergone elective genitourinary surgery in a tertiary care hospital to investigate the rationality of prophylactic use of antibiotics in genitourinary surgery according to the American Urological Association recommendations 2011. All patients undergoing genitourinary surgery had received antibiotics. Injectable antibiotic was administered within 1 hr before surgery in 95% cases and 1-2 hrs before surgery in 5% cases. Preoperatively single antibiotic was used in 92%, two in 7% and three in 1% cases whereas postoperatively single antibiotic was used in 91%, two in 7% and three in 2% cases. Most commonly administered antibiotic group preoperatively as well as postoperatively was a second generation cephalosporin, cefuroxime along with a beta lactamase inhibitor, sulbactam (90% cases) followed by the combination of cefuroxime and an aminoglycoside, amikacin (4% preoperatively and 5% cases postoperatively). The number and group of antibiotic used preoperatively and postoperatively were quite identical. The average duration of antibiotic use was 3-10 days. The prophylactic use of antimicrobials in genitourinary surgeries in this hospital was rational with respect to time of administration and choice of antibiotic group. However, the duration of antimicrobial use was highly irrational which must be controlled to prevent the emergence of resistance strains and decrease the adverse effects and cost of health care to the patient.