Initial randomised studies of chemotherapy and endocrine therapy showed that systemic treatments had a substantial impact on the survival of women with early breast cancer. The original assumption was that the efficacy of these treatments was limited to those patients presenting with more adverse prognostic features. Subsequently, meta-analyses of randomised trials revealed that the benefits of chemotherapy and endocrine therapy are not mutually exclusive and extend to all the prognostic subgroups. However, the absolute benefit varies according to baseline characteristics such as tumour stage and other biological factors. Over the last 10 years, considerable progress has been made with the introduction of new drugs into the adjuvant and neoadjuvant treatment of women with breast cancer. Taxanes and third-generation aromatase inhibitors are providing proof of additional benefits compared with standard reference treatments. In parallel, research on the biology of breast cancer is establishing novel prognostic and predictive factors, which may allow better treatment tailoring. Currently, however, women with early breast cancer and their doctors face the difficult task of making therapeutic decisions often based on early results from positive studies. In a disease where follow up is crucial to fully assess the benefit and long-term toxicities of an intervention, current knowledge leaves unanswered questions that generate debate and controversy. This review will summarise recent results from randomised trials of adjuvant and neoadjuvant therapy in women with early breast cancer and focus on the current controversies.