We retrospectively studied 295 men who had undergone herniorrhaphy under spinal or general endotracheal anesthesia to determine the incidence of postoperative urinary retention and to assess factors influencing it. The type and location of hernia had no effect on retention. In contrast, the use of general anesthesia, patient age above 53 years, and perioperative administration of more than 1,200 mL of fluid were significantly associated with an increase in retention. Our results suggest that urinary retention after herniorrhaphy may be prevented by limiting the amount of fluid given perioperatively and by using a spinal anesthetic, especially in older patients.