SYNOPSISStatistics derived from a sample of 1391 schoolgirls drawn from both state and private schools showed the mean age of menarche to be 12.65 years. Selected schools were included to give a representative sample in terms of geographical and social class distribution. The onset of puberty was found to be normally distributed within the age range 9 years to 15 years 8 months. After an examination of the results of previous Australian studies, evidence was found which suggested a secular trend in the onset of puberty with fluctuations paralleling times of economic crisis.