A sample of 4554 of newborn was used to study the distribution of the head circumference measure shortly after birth. The sample is part of the cohort born in Ribeirão Preto, Brazil, from June 1st. 1978 to May 31st. 1979. It was possible to show that such measure follows a normal distribution for both sex (either separately or together) and to calculate 'normality limits' for practical use.