STUDY OBJECTIVE--The aim of the study was to investigate the effect of different pattern of childbearing on total mortality. DESIGN--A cohort study with all currently married women aged 25 years or more at the Norwegian census in 1970 with follow up to the end of 1985. Information on childbearing was obtained by questionnaires collected by enumerators. Follow up on death was found by a linkage based on the unique Norwegian identification number, between census information and the death register in the Central Bureau of Statistics. SETTING--The study was a national population survey. PARTICIPANTS--A total of 822,593 women with 11.5 million years of follow up and 112,023 deaths. MAIN RESULTS--Nulliparous women had higher mortality than parous women in all age groups. Parity showed a weak association with increasing mortality among high parous women. Lowest mortality was found for parous women with 2-4 children and a late first and last birth, adjusted for socioeconomic group by level of women's education. CONCLUSION--The findings indicate that postponed childbearing may benefit the health of women.