Objective To examine how (a) parity and (b) mode of birth were associated with later Quality of Life (QOL) in young adult women, with a mean follow-up of 11.0 years. Design Prospective cohort study Setting Australia r sample A total of 7770 women participating in the 1973-1978 cohort of the Longitudinal Study of Women's Health. Methods Linear regression models were used to estimate (1) prospective associations between parity and mode of birth with eight subscale and two summary scores of the SF36, assessed after a mean follow-up of 11 years., and (2) differences between SF36 scores at follow up for women in different parity and mode of birth categories. Main outcome measure Quality of Life as measured by the SF36 Results Women experiencing no births (parity 0) and one birth (parity 1) had lower scores on all the physical health measures, and on some mental health measures, than women who had 2 births (parity 2) (all p<0.05). Conclusions Parity and mode of birth may have long-term implications for women's physical and mental health. Both childless and women with only one child had poorer physical and mental health than their peers with two children. Women with only caesarean section(s) also had poorer health than women who had vaginal birth/s.