The frequency of aromatase inhibitor (AI)–associated arthralgia and/or bone pain in clinical practice is not known. Fifty-six consecutive patients with breast cancer not on clinical trials who were receiving AIs in a clinical practice were interviewed regarding occurrence of worsening or new arthralgia and/or bone pain after starting AI therapy. The occurrence, character, severity, and resolution of pain were evaluated. Arthralgia and/or bone pain was reported in 61% of patients. It was severe in 30%, continuous in 41%, central in 50%, peripheral in 79%, and resulted in discontinuation of the drug in 20% of patients. Effective therapies in controlling pain were acetaminophen, 29%; nonsteroidal anti-inflammatory drugs, 50%; opiates, 18%, and glucosamine in 15% of patients. Despite this, 20% of patients discontinued AI therapy because of pain. Aromatase inhibitor–associated pain is more frequent in patients not in clincal trials than previously appreciated in clinical trials. Improved patient education is needed, and prompt therapeutic management of pain is required to ensure continued drug treatment and improved quality of life.