Breast cancer is the most frequently diagnosed malignancy in women, with over 200,000 new cases diagnosed each year. Adjuvant systemic endocrine therapy has demonstrated its benefits in reducing the risk of occult micro metastatic infiltration by preventing breast cancer cells from receiving endogenous estrogen stimulation. Initial adjuvant treatment with an aromatase inhibitor (AI) is considered the standard of care for most postmenopausal women with node-positive and high-risk node-negative estrogen receptor (ER)-positive breast cancer. Aromatase inhibitors (AIs) are generally preferred over tamoxifen due to their effectiveness in preventing breast cancer recurrence post surgery and when tamoxifen side effects are to be avoided. When compared with tamoxifen, AIs are associated with significantly improved disease-free survival, however no OS advantage has been noted. Potential toxicities such as bone loss, dyslipidemia, musculoskeletal and cardiovascular health issues should be taken into consideration when AIs are to be used.