We investigated if it is possible to use the data collected in twins to identify areas with high rates of operative deliveries, preterm deliveries and low birthweight infants in singletons. Our data correspond to all deliveries registered in Belgium in 1983. A significant correlation was found between the rates of cesarean sections in twins and in singletons. A significant correlation was also found between the rate of deliveries at a gestational age of less than 32 weeks in twins and the rate of deliveries at less than 37 weeks in singletons. However, correlations between other preterm rates, low birthweight rates and vacuum extraction or forceps rates, were nonsignificant. We conclude that the use of twins as tracers of the quality of care in singletons is of limited value.