Several international studies have found that survival from breast cancer is lower in the United Kingdom than in some other European countries. We have compared breast cancer survival between the national populations of England, Norway and Sweden, with a view to identifying subsets of patients with particularly good or adverse survival outcomes. We extracted cases of breast cancer in women diagnosed 1996-2004 from the national cancer registries of the 3 countries. The study comprised 303,657 English cases, 24,919 Norwegian cases and 57,512 cases from Sweden. Follow-up was in 2001-2004. The main outcome measures were 5-year cumulative relative survival and excess death rates, stratified by age and period of follow-up. In comparison with Norway and Sweden, the excess mortality in England was particularly pronounced in the first month and in the first year after diagnosis, and generally more marked in the oldest age groups. Compared with Norwegian patients, 81% of the excess deaths in the English patients occurred in the first 2 years after diagnosis. Our findings emphasise the importance of awareness of symptoms and early detection as the main strategy to improve breast cancer survival in the United Kingdom.