Adjuvant radiotherapy after breast conserving surgery or mastectomy has an established role in the treatment of early stage invasive breast cancer. It improves quality of life by maximising local control and improves overall survival. In older patients however the risk of death from other causes is such that a survival benefit is not always present. The risk of local failure is very low for Stage 1 Luminal A disease but can be high for all breast cancer phenotypes, depending on T and N stage. Breast radiotherapy is generally well tolerated by older patients although fatigue may be significant. Careful consideration must be given to the individual patient’s performance status, medical co-morbidities and personal wishes, as well as to the estimated recurrence risk of that individual’s tumour, in order minimise the potential for unnecessary treatment but equally to avoid under treatment of higher risk disease simply because of the patient’s age.