The anterior fontanelle size of 303 Israeli neonates was measured. The purpose was to establish normal values of fontanelle size in different Israeli ethnic groups. The size of the fontanelle was calculated as length plus width, the mean size for the whole population being 2.06 +/- 0.6 cm. These results correlate with those of Western, White, healthy neonates. No difference in anterior fontanelle size for the different ethnic groups or between sexes was found. Knowledge of the normal variation in anterior fontanelle size may be of help in diagnosing skeletal developmental disorders. The method used is simple and accurate and can be used in the routine neonatal examination.