Background: Sentinel node biopsy (SNB) is now the standard of care for women with earlystage breast cancer. Despite lower morbidity than axillary lymph node dissection, widespread variation in SNB rates by non-clinical factors persists. We explored the factors associated with SNB usage and changes in those associations over time for recently diagnosed women. Methods: We report here on a linked population-based cancer registry and hospital inpatient admission data set for 5577 women aged at least 20 years diagnosed with a first primary invasive early-stage node-negative breast cancer from July 2008 to 2012 in Queensland, Australia, who underwent breast cancer-related surgery within 2 years of diagnosis. Multivariate logistic regression was used to model predictors of SNB separately for 5172 women with ≤30 mm tumours and 405 with 31 to ≤50 mm tumours. Results: Overall, 3972 (77%) women with ≤30 mm tumours and 221 (55%) of those with larger tumours underwent SNB. Usage increased over time for both cohorts but was consistently lower among those with larger tumours. A more recent diagnosis, having breastconserving surgery, living in more accessible areas and attending a private or high-volume hospital independently increased the odds of SNB for both cohorts. There was no evidence that the geographical disparity had reduced over the study period for either cohort. Conclusion: Geographical disparities to accessing SNB persist. Efforts to promote multidisciplinary care and facilitate education in healthcare changes through innovative solutions using emerging technologies as well as targeted research to identify the barriers to equitable access remain critical.