To examine the relationship between operating time and reoperation for recurrence and other complications in groin hernia repairs. Observational population-based register study. Data from the nationwide Swedish Hernia Register, which prospectively collects data from almost all groin hernia repairs performed in Sweden. There were 123,917 primary groin hernia repairs recorded in the Swedish Hernia Register from January 1, 1998, through December 31, 2007. Relative risk of reoperation for recurrence and odds ratios for postoperative complications in 4 operating time groups. The relative risk of reoperation for recurrence of all patients operated on in less than 36 minutes was 26% higher than that of all patients with an operating time of more than 66 minutes (1.26; 95% CI, 1.11-1.43). Because the Lichtenstein procedure is the standard procedure in Sweden today, its results were also analyzed separately. In this homogeneous group, the difference was even more striking with an increased relative risk of 45% (1.45; 95% CI, 1.21-1.75). The odds ratio for infection and other postoperative complications increased with increasing operating time. A significant decrease in reoperation for recurrence with increasing operating time exhorts the hernia surgeon to avoid speed and to maintain thoroughness throughout the procedure.