The economic impact on individuals with breast cancer is not well understood. We sought to identify and describe the direct and indirect economic losses to breast cancer survivors in Australia. A longitudinal, population-based study of 287 women was used to explore economic outcomes (costs and lost income) for women with breast cancer 0-18 months post-diagnosis. Survey methods collected data on out-of-pocket costs, care-giving support, paid and unpaid work reductions, and perceptions from participants on these financial impacts. Bootstrapping was used to estimate 95% confidence intervals around means. Data were sub-grouped by cost type, age category and disease severity. Lost income, health service expenditures and lost unpaid work were the greatest sources of economic burden. Women with positive lymph nodes reported significantly higher costs than those with negative lymph nodes (US$6674 versus US$3533, p<0.001), and younger women (< or =50 years) with positive lymph nodes experienced costs 80% greater than older women (US$8880 versus US$4937, p<0.001). Economic costs related to breast cancer may continue to affect women 18 months post-diagnosis. Economic research adds an important dimension for understanding the impact of breast cancer, and findings may be used to help improve supportive care services for women and families confronted by this disease.