There is an abundance of evidence that adjuvant systemic therapy with chemotherapy or endocrine therapy results in better survival for all patients with resectable breast cancer. The absolute 10-year survival advantage however varies for the different patient groups. Therefore, for each individual patient the choice of adjuvant therapy must take into account the potential benefits and the possible side effects. A group of medical oncologists from the Dutch National Breast Cancer Platform (NABON) and the Dutch Society for Medical Oncology (NVMO) prepared a guideline for the treatment of patients with early resectable breast cancer. The criterium for choosing adjuvant systemic therapy for the individual patient is an expected increase in 10-year survival of 5% or more. In the guideline a difference is made between patients with and without axillary lymph node metastasis. In patients with axillary lymph node metastasis the choice for adjuvant systemic therapy depends on the following prognostic factors: menopausal status, age, and the presence of estrogen and progesterone receptors in the tumour. In patients without axillary lymph node metastasis the choice depends also on the following prognostic factors: the size of the tumour, the mitotic activity index, or the histopathologic grade of differentiation.