Aim: Sentinel lymph node biopsy (SLNB) without completion axillary lymph node dissection (ALND) is replacing ALND as the axillary staging procedure of choice in breast cancer patients with a clinically negative axilla even though it is unclear whether this influences patient survival. Our aim was to compare the survival of breast cancer patients with a negative SLNB without completion ALND to that of extensive ALND-negative patients. Methods: Eindhoven Cancer Registry data on breast cancer patients diagnosed between 1989 and 2002 with follow-up to I January 2005 was used. Survival was compared between 880 SLNB-negative women (median follow-up 3.6 years) without completion ALND and 1681 ALND-negative women (median follow-up 7.7 years) with at least 10 axillary nodes removed. Conclusions were made after correcting for age. turnout size. tumour location, tumour histology, tumour grade, mitotic activity index (MAI), hormone receptor status, and local and systemic treatment in uni- and multivariate analyses. Results: Crude 5-year survival rates were 85% for ALND-negative and 89% for SLNB-negative breast cancer patients (p = 0.026). After correction for potential confounders in a multivariate Cox regression analyses, the hazard ratio for overall mortality of ALND-negative compared to SLNB-negative patients without completion ALND was 1.23 (95% confidence interval: 0.93-1.64). Conclusion: Survival after a SLNB without completion ALND is at least equivalent to after an extensive ALND in node-negative breast cancer patients. This means that the SLNB only can safely replace ALND as the procedure of choice for axillary staging in breast cancer patients with a clinically negative axilla.