Sotos syndrome is characterised by pre- and post-natal growth acceleration, advanced bone age, developmental delay and a typical facial Gestalt. We have evaluated 45 individuals with Sotos syndrome who were between age 1 and 25 years, in order to better define the change in facial appearance over time. In each individual, a thorough assessment was made, serial photographs were reviewed, and a series of anthropometric craniofacial measurements was obtained. These were compared with age- and sex-matched normal standards. Both clinical and anthropometric evaluations show that the facial appearance which most clinical geneticists would regard as "classical" is established early in life. The head is large and dolichocephalic, with a rounded and prominent forehead, accentuated by frontoparietal balding. There is narrowing at the temples, fullness of the cheeks, and tapering to a pointed chin. With time, the normal process of facial change occurs, superimposed on that typical Gestalt. As the face lengthens, the dominance of the forehead diminishes and the chin achieves greater prominence. The mandible is long and narrow inferiorly, square or pointed, but prognathism is rare. In a small proportion of patients, a rounder face early in life may challenge diagnosis, but follow-up of these large newborn and older infants should allow diagnosis by early childhood. Visualisation of pattern profiles at different ages, supplemented by statistical measures of variability and similarity, support the clinical impressions outlined above.