The aim of this study was to compare the efficacy of single-dose intravenous cefazolin prophylaxis with single-dose oral ciprofloxacin prophylaxis in patients undergoing tension-free inguinal hernia repair with polypropylene mesh. In a prospective and randomized setting, 395 patients received either a single dose of 500mg of ciprofloxacin orally, 1–2h before the operation, or a single dose of 1g cefazolin intravenously on induction of anaesthesia. The primary outcome was to determine the wound infection rate within one year. The overall infection among the entire study population was 2% (eight of 395) including 2% (four of 199) of those receiving intravenous cefazolin and 2% (four of 196) of those treated with oral ciprofloxacin. There was no statistically significant difference between groups (P=0.59). All the infections were superficial incisional surgical site infections, and none progressed to a deep infection. Escherichia coli was the most commonly isolated bacterium. None of the infected patients developed recurrence of hernia. The rate of recurrence was 1.3% (five of 395) at one year including 2% (four of 199) of those receiving cefazolin and 0.5% (one of 196) of those receiving ciprofloxacin. Oral ciprofloxacin prophylaxis was found to be an attractive option with its wide antibacterial spectrum, low cost and ease of administration in patients undergoing tension-free inguinal hernia repair with polypropylene mesh.