We examined published reports on the use of aromatase inhibitors in postmenopausal patients with hormone receptor-positive breast cancer. Our data were obtained through a MEDLINE search of literature published in English. Current data indicate that aromatase inhibitors are equivalent or superior to tamoxifen as first-line therapy for metastatic breast cancer and as neoadjuvant treatment for primary breast cancer. In addition, randomized studies have shown that aromatase inhibitors can be administered instead of tamoxifen as a single agent for 5 years or sequentially with tamoxifen for 5 or 10 years. These choices should be discussed with the patient, considering the estimated risk for recurrence and other associated comorbid conditions such as osteoporosis and thromboembolism.