In 1995 a survey was conducted in four schools in the city of Jeddah to determine the age of menarche in this population. Nine hundred and twenty-nine girls were studied. The mean age at menarche was 15.1 years, and this was later than most other Arabic countries and most Western countries, Social class was found to influence age at menarche, but the differences in relation to family size did not reach statistical significance. The reason for differences between population is discussed.