Background: A surveillance system was established at the Aga Khan University Hospital in Karachi, Pakistan, to determine surgical wound infection (SWI) rates, trends, and risk factors; and to compare rates with those reported by the National Nosocomial Infection Surveillance (NNIS) system of the Centers for Disease Control and Prevention. Methods: Surveillance was performed from January 1997 to December 1999. Risk categorization was on the basis of the NNIS system. P < .05 was set for statistically significant difference between groups. Data were analyzed using the Epi-Info software (version 6.04, CDC, Atlanta, Ga). Results: Overall SWI rates for the NNIS risk categories 0, 1, 2, and 3 were 1.9%, 3.7%, 6.7%, and 5.1%, respectively. SWI rate in 0 risk category decreased from 3% in 1997 to 1.1% in 1999 (P = .06). Multivariate analysis showed that SWI rates were higher after mastectomy (odds ratio [OR] 4.28, 95% confidence interval [CI] 1.8-10), hernia repair (OR 3.28, 95% CI 1.6-6.7), gastrointestinal resection (OR 2.2, 95% CI 0.88-5.9), skin procedures (OR 1.97, 95% CI 0.89-4.3), appendectomy OR 0.57, 95% CI 0.20-1.60, and miscellaneous procedures (OR 3.6, 95% CI 1.6-7.7), as compared with cholecystectomy. Other risk factors were contaminated type of operation (OR 2.6, 95% CI 1.2-5.5), and duration of operation exceeding the NNIS standard of "T" hours (OR 2.6, 95% CI 1.7-4). Conclusion: The SWI rates at the Aga Khan University Hospital are higher than the NNIS standards. There was a downward trend in the SWI rates during the surveillance period. A decrease in the duration of surgical procedures could further reduce the risk.