This study was designed to determine the prevalence of intrauterine growth restriction in neonates with gastroschisis and to evaluate the accuracy of the ultrasonographic diagnosis of intrauterine growth restriction. Birth weight and gestational age were determined for 46 infants diagnosed prenatally as having gastroschisis. Biometric data were analysed for the 30 pregnancies in which an examination was conducted within 1 week of delivery. Fetal growth parameters were compared with norms for gestational age. The prevalence of intrauterine growth restriction in the entire study group was 24% with a mean birth weight of 2401 +/- 508 g. Ultrasonographic estimated fetal weight was significantly less than birth weight (mean, 2079 +/- 508 g versus 2331 +/- 512 g, respectively; P < 0.0001). Intrauterine growth restriction was predicted in 43% of infants but was present in only 23%. The percentage difference between measured abdominal circumference and gestational age norm was significantly more than for biparietal diameter and for femur length (P < 0.001). Of the three biometric measures, only the difference between measured abdominal circumference and gestational age norms and the difference between estimated fetal weight and birth weight showed a significant correlation. Both abdominal circumference and femur length correlated with the difference between estimated fetal weight and birth weight. We conclude that the prevalence of intrauterine growth restriction is increased in infants with gastroschisis but is overestimated with prenatal ultrasonography, primarily because of smaller than average abdominal circumference measurements.