BACKGROUND: This longitudinal analysis examines how patterns of contraceptive use changed over 11 years among Australian women born between 1973 and 1978. STUDY DESIGN: The analysis included 6708 women sampled from the Australian universal health insurance database who completed four self-report postal surveys between 1996 and 2006. Change over time in use of any method of contraception and the common single methods of the oral contraceptive pill and condom was examined using a longitudinal logistic regression model. RESULTS: The oral contraceptive pill was the most commonly used single method at each survey (27-44%) but decreased over time. Over time, contraceptive users were increasingly more likely to be single or in a de facto relationship or to have had two or more births. CONCLUSIONS: Women's contraceptive use and the factors associated with contraceptive use change over time as women move into relationships, try to conceive, have babies and complete their families.