SummaryIntra-uterine growth retardation may be classified by ultrasonography into symmetrical and asymmetrical. In the symmetrical type the biparietal diameter increases in parallel with, but below, the normal growth curve and the head to abdominal circumference ratio is normal. In the asymmetrical group the biparietal diameter is either normal or flattened, and deviates from the normal curve, whilst the head to abdomen circumference ratio is above normal in both situations. We have reviewed 34 cases of intra–uterine growth retarded fetuses. Ten of these were symmetrical of which five had malformations. Twenty-four were asymmetrical and in eighteen of them the mother had hypertensive disease. The course and outcome of pregnancy and labour were different in these two groups. This classification can be useful in planning the clinical management of pregnancies with fetal growth retardation.