Intrauterine growth curves require periodic revision because of changes in population, socio-economic factors and technology used in obstetric care. Anthropometric measurements were derived from consecutive livebirths in the Royal Women's Hospital in 1979 and all those born before 35 weeks in 1977 and 1978; at gestational ages less than 30 weeks, data previously published was also incorporated. Infants were included if an ultrasonic examination of the uterus had been performed in the first 20 weeks of pregnancy or gestation based on "certain" menstrual history was confirmed clinically. From data on 3120 infants, intrauterine growth curves from 24-42 weeks' gestation were prepared; compared with births in the same hospital in 1966, there was generally an elevation of all centiles, particularly so for the 10th centile for weight after 37 weeks' gestation. Factors in the infant such as sex and ethnic origin and also maternal factors, especially pregnancy weight and height should be considered when using standard intrauterine growth charts.