This cross-sectional design was to identify the age at menopause of Korean women using a national sample, and to examine relationships between age at menopause and the anthropometric, sociodemographic, biological and life style behavioral factors. Two thousand eight hundred seven naturally postmenopausal women aged between 41-65 years were recruited by self-selection from 7 metropolitans and 6 provinces in Korea from Dec. 20, 1998 to April 30, 1999. The age at menopause of Korean women was 49.2 years (mean) and 50.0 years (median). The range of age at menopause was 33.0 to 61.0 years. The significant influencing factors on age at menopause were body mass index, mother's and sister's age at menopause, alcohol use, physical activity, coffee preference, and residential area. The menopausal age of Korean women has slightly increased compared to a previous study.