In a sample of approx. 19 000 Polish schoolgirls from the three largest cities of the Upper Silesia conurbation, menarcheal age was studied in relation to parental education (four levels) and father's occupation (12 groups). Menarcheal age tends to increase with decreasing parental education, although the gradient is not steep. When families below a certain level of economic standing are discarded from the best-educated and the least-well-educated groups, mean menarcheal age, surprisingly, decreases much more in the former than in the latter. Mean menarcheal ages for girls from different occupational groups range from 12.82 to 13.30 years and form the following sequence, in increasing order: managers--police--non-technical professionals--engineers, technicians and foremen--skilled industrial workers and small businessmen--unskilled workers--coal-miners. Mean menarcheal age for an occupational group is strongly dependent upon the group's socio-economic status, the latter being defined in terms of parental education, family income, family size, and dwelling conditions. However, daughters of men in the police force mature significantly earlier, and daughters of coal-miners significantly later, than would be expected from each group's rank in socio-economic status. The findings are compared with the results of other recent studies of social gradients in menarcheal age in Poland.