Brazil has one of the highest rates of caesarean section in the world. Patterns of caesarean sections were studied in a cohort of 5960 mothers followed from 1982 to 1986 in southern Brazil. Overall, 27.9% were delivered by caesarean section in 1982, this proportion being 30% for nulliparae, 80% for second deliveries when the first was by caesarean, and over 99% for third births when the first two were by caesarean. Socioeconomic status and requests for sterilisation by tubal ligation were important underlying factors. 9.4% of the women were sterilised during a caesarean section (3.7% in the lowest income group and 20.2% in the highest). 31% of women who had had their first child by a caesarean section and who were having a second operative delivery were sterilised. The high rates of caesarean sections and accompanying sterilisations reflect the lack of appropriate reproductive and contraceptive policies in the country.