More than 50% of breast cancers are diagnosed in women aged 65 years or older, a quickly growing segment of the population. Healthy older women should be offered state-of-the-art screening and treatment for breast cancer, including mammography, surgery, radiation therapy, and adjuvant therapy for early stage tumors. Clinical trials focusing on the role of adjuvant treatment in older women with breast cancer are of chief importance. The optimal treatment for older women with life-threatening, comorbid conditions may be primary treatment with tamoxifen or adjuvant therapy with tamoxifen alone after definitive surgery. Outside the clinical trials setting, metastatic disease should be treated similarly in all age groups.