Breast cancer affects mostly older women but there are no guidelines especially devoted to adjuvant chemotherapy for this population. In this context, this study was carried out in a population-based cohort of French elderly women with breast cancer, to check adherence to the existing national guidelines according to the women's age, taking into account the evolution of the situation over time for women requiring chemotherapy. Between October 2006 and December 2008, all consecutive women included in the French Health registry for a biopsy-proven primary nonmetastatic breast cancer, aged 65-80 years at diagnosis, and living in South Eastern France, were asked to participate in a cohort study. Medical information was collected from physicians. The study population was restricted to the 223 women who were recommended adjuvant chemotherapy according to national guidelines. Those who received chemotherapy were compared to those who did not receive this treatment. Among these 223 women 55% had received chemotherapy. Only three women refused the treatment. Less than 8% have had a geriatric assessment before treatment decision and only two were proposed to participate in a clinical trial. After adjustment for comorbidity score, tumor characteristics, socio-demographic characteristics, and year of diagnosis, increasing patient age was independently associated with decreased guideline concordance for adjuvant chemotherapy. Women aged 75-80 years received chemotherapy more than four times less often than women aged 65-74 years. However, the percentage of women who received chemotherapy increased from 33% to 58% between 2006 and 2008, in parallel with the setting up of Onco-Geriatric Coordination Units in the area. In France, chronological age remains a barrier to receive chemotherapy for older breast cancer women but the establishment of a formal collaboration between oncologists and geriatricians seems to be an effective way to improve care delivery in this population.