It is clearly defined through a number of authoritative studies that the age of menarche influenced by the various combined factocs such as nutrition status, physical status, physical growth and development status, socio-economic status, locality, culture, education level, climate, race heredity etc. In order to obtain statistical data regarding the menarche of Korean school girls, anthers investigated on 4207 middle school girls and 703 woman college students in Seoul and Teagu during the period of September 10 to 30, 1973 and the result are summarized as followings; 1. The rates of menses experience by years were 18.2% in the age group of 12 years girls, 31.9% in 13 years, 64.6% in 14 years, 89.8% in 15 years, 98.1% in 16 years respectvely. 2. The average age of menarche for the 2504 school girls who were born during the yrar of 1957-1961 is 13.4 years with the rang of 9 years to 16 years. And the most frequent age of menarche is 13 years. 3. The average age of menarche for the 703 woman college students who were born during the year of 1950-1954 is 14.3 years with the rang of 9 years to 18 years. And the most frequent age if menarche is 13 years. 4. The appearence of menarche is most common in August (20.7%) for the group who were born during the year of 1957-1961 and most rear in November (4.2%). And it is also most common in August (19.9%) for the group who were born puring the year of 1950-1954 but most rear in June (3.4%).