A multigenerational delay in the rise of breast cancer incidence rates has been documented among immigrants to the United States. Prompted by this observation, this study examines three breast cancer risk factors, age at menarche, parity, and age at menopause, in relation to each other and in relation to migration status and language most often used in U.S. Hispanic populations. Mexican American (n = 1,502), Cuban American (n = 534), and Puerto Rican (n = 700) women, aged 30-74 years, were drawn from the Hispanic Health and Nutrition Examination Survey (HHANES), 1982-1984. Mean recalled age at menarche was significantly later among first generation compared to second generation immigrants in both Mexican Americans (13.3 vs 12.8 years) and Puerto Ricans (12.8 vs 11.9 years). Among Mexican Americans, more children were reported by first generation immigrants than women of the third or more generations (4.9 vs 4.0 children) and by Spanish speakers compared to women who used English more frequently (4.5 vs 3.3 children). Mean and median ages at menopause were later among second generation Mexican American women than first generation women. There was a small, significant, positive correlation between recalled ages at menarche and menopause within each of the first generation Hispanic subgroups. The unique positive correlation between ages at menarche and menopause among first generation immigrants may relate to having spent early years in the country of origin and later years in the United States. Am. J. Hum. Biol. 10:451-457, 1998. Β© 1998 Wiley-Liss, Inc.