The long-term effects of vacuum and forceps deliveries are largely unknown. We determined the long-term outcome of instrumental deliveries in 52 282 infants born in Jerusalem between 1964 and 1972. For each individual, events at birth were related to results of an intelligence test and medical examination done at 17 years of age by the Israeli Defence Forces draft board. 1747 individuals were delivered by vacuum, 937 by forceps, 47 500 by spontaneous delivery, and 2098 by caesarean section. Crude data showed that mean intelligence scores at 17 were significantly higher (p<0·0001) in the vacuum and forceps deliveries groups than in the spontaneous-delivery group; however, after adjustment for confounding factors by stepwise multiple regression, these differences were no longer seen. Although the forceps-delivery group had functional impairment of feet, vision, and retina compared with the spontaneous-delivery group, and the vacuum-extraction group had impairment of the legs, differences were small. Our findings suggest that infants delivered by vacuum or forceps are not at risk of physical and congnitive impairment at 17 years of age.