The management of a child with an irreducible ovary remains inconsistent in pediatric surgical centers. An informal survey of senior pediatric surgeons and an extensive review of the literature showed a prevailing view that the trapped ovary is not at significant risk of vascular compromise. Two recent cases prompted a review of our experience from 1984 to 1989, during which 1,699 children with inguinal hernias underwent operation, 386 (23%) of whom were girls. Fifteen girls (4%) had irreducible ovaries present at the time of operation and in 4 of the 15 (27%) the ovary was twisted and infarcted. Two of the 4 girls were known to have an irreducible ovary prior to the day of operation--1 was noted 2 months earlier and 1 was noted 1 month earlier. At the time of the initial diagnosis, neither patient had physical findings of vascular compromise of the ovary. In the other two girls, evidence of an infarcted ovary was present when the hernia was first diagnosed and an emergency operation was performed. A 27% incidence of torsion and strangulation of irreducible ovaries appears to be high, but reports of strangulated ovaries have been reported in 2% to 33% of other series. The normal anatomy is altered when an ovary is trapped in a hernia sac, and these changes make torsion more likely. Although an irreducible ovary is not at great risk of compression of its blood supply, this report identifies a significant risk of torsion. This risk warrants treating the asymptomatic irreducible ovary as any other incarcerated hernia--as a true emergency.