The addition of adjuvant chemotherapy in early breast cancer improves overall survival by approximately 10%. Recommendations favor the use of anthracyclines and taxanes in patients with luminal B disease, while the use of an anthracycline, taxane and alkylating agent is recommended in triple-negative disease. In luminal B disease, the addition of chemotherapy to endocrine treatment depends on estrogen receptor expression and overall risk. Chemotherapy is not recommended in most patients with luminal A (highly hormone-sensitive and low proliferation) breast cancer. A major controversy is the addition of adjuvant chemotherapy to endocrine treatment in patients with estrogen receptor-positive breast cancer. In some of these patients, multigene signatures such as the 21-gene recurrence score may be a useful addition to histopathology. The introduction of molecular subtypes and gene signatures improves the complexity of early breast cancer treatment, and individual institutes have to find their policy based on their histopathological information and the availability of gene signatures.