This article uses the mean age at menarche of women in China as an indicator of changes in the standard of living during the 20th century. It discusses the difficulties of using this indicator. It finds that the mean age of menarche stagnated at 16 to 17 years for women born during the period between the 1880s and 1930s. The age at menarche decreased in some urban areas, indicating improving living standards in, for example, Beijing and Shanghai. The mean age at menarche increased for 1940s’ birth cohorts, in relation not only to the warfare of the 1940s but also the famine of 1959–1962. The mean age at menarche decreased in a sustained way for women born during the 1950s to early 2000s. The decrease is associated with increasing educational attainment since the 1940s and also improvements in nutrition, hygiene and healthcare.