Background: This study aimed to determine the impact of socio-economic and geographic disparities on disease stage at diagnosis according to age in breast cancer (BC) patients. Secondary purpose was to describe survival. Methods: All women with primary invasive BC, diagnosed from 1998 to 2009 in the department of Côte d’Or were retrospectively selected using data from the Côte d’Or BC registry. European transnational ecological deprivation index (French European Deprivation Index) was used to measure the socio-economic environment. Relationships between socio-geographic deprivation and disease stage at diagnosis according to age were assessed by a multilevel ordered logistic regression model. Relative survival rates (RSRs) were given at 5 years according to tumour and patients characteristics. Results: In total, 4364 women were included. In multivariable analysis, socio-economic deprivation was associated with disease stage at diagnosis. Women aged between 50 and 74 years and living in deprived areas were more often diagnosed with advanced tumour stages (stages II/III vs. I or stages IV vs. II/III) with odds ratio = 1.27 (1.01–1.60). RSRs were lowest in women living in the most deprived area compared with those living in most affluent area with RSR = 88.4% (85.9–90.4) and 92.6% (90.5–94.2), respectively. Conclusions: Socio-economic factors affected tumour stage at diagnosis and survival. Living in a deprived area was linked to advanced-stage BC at diagnosis only in women aged 50–74 years. This is probably due to the socio-economic disparities in participation in organized BC screening programmes. Furthermore, living in deprived area was associated with a poor survival rate.