The areolar size was measured in a group of 755 school boys, aged 7 to 20 yrs. At the onset of puberty a sudden increase in areolar size has been noted, with a gradual increase in areolar size as pubertal development proceeds. The increase in areolar size must be seen as a pubertal phenomenon, resulting from a peripheral influence of sexual hormones, but a significant positive relationship to body size during this period of life must also be taken into account.