Background: In line with current Australian early breast cancer management guidelines, more women are having breast conserving surgery to treat breast cancer when appropriate. Some women will undergo further surgery because of involved margins, early local relapse, or other factors including patient choice. The aim of this study was to investigate whether socio-economic, demographic or hospital factors were associated with the risk of re-excision or subsequent mastectomy. Methods: A record linkage population-based study on 12 711 women diagnosed with breast cancer in Western Australia from 1982 to 2000 who underwent breast surgery within 12 months of diagnosis was performed. Logistic regression was used to identify social, demographic and hospital factors associated with the risk of undergoing further surgery following initial breast conservingsurgery. Results: The proportion of women undergoing initial breast conserving surgery doubled from 33... in 1982–1985 to 72... in 1998–2000. The proportion of women who underwent further surgery following initial breast conserving surgery decreased from 50 to 30... over the same period. The risk of re-excision or subsequent mastectomy was between 2.4 (95... CI 1.7–3.4) and 5.0 (95... CI 3.4–7.4) times greater if initial surgery was performed in a non-metropolitan hospital compared to Perth hospitals. Younger women were between 1.7 (95... CI 1.4–2.0) and 2.1 (95... CI 1.5–3.0) times more likely to undergo re-excisions compared to women aged 50–64 years of age. Conclusions: Young women and women initially treated in non-metropolitan hospitals were at an increased risk of re-excision or a subsequent mastectomy following initial breast conserving surgery to treat breast cancer. Efforts need to be directed towards improving specialist health services outside of Perth if women continue to be treated for breast cancer in non-metropolitan hospitals.