Radiation therapy is a key treatment of breast cancer. Elderly patients with associated diseases that modify their performance status do not tolerate long periods of daily irradiation. The objective of this study is to analyze the results of weekly hypofractionated treatment in these patients. Between 1992 and 2016, we included 486 elderly patients presenting concomitant pathology or sociofamilial problems in which it was not feasible to propose conventional treatment. They were treated with conservative surgery or mastectomy and then adjuvant hypofractionated irradiation, administering 5 Gy or 6.25 Gy in 6 fractions, once a week (total dose 30-37.5 Gy) over 6 weeks. Breast cancer overall survival according to the Kaplan-Meier method at 5 years was 74.2% ± 2.3%; breast cancer disease-free survival was 90% ± 1.6%; local relapse-free survival was 96.5% ± 1% showing that patients die more from other causes and not from their neoplasia. Acute dermatitis was mild (75.6% of the patients grades I-III) and 30.6% had moderate chronic fibrosis. The once-weekly hypofractionated radiotherapy is a feasible and convenient option for elderly patients with breast cancer. It is a safe treatment modality with similar survival and local control results compared to standard fractionation, while the side effects are acceptable.