Purpose:To assess the joint symptoms and the impact on patients’ health-related quality of life (HRQOL) due to 5 years of anastrozole from the baseline data in the N-SAS BC 05 trial, a randomized clinical trial was designed to assess the efficacy of 5 additional years of anastrozole among women with breast cancer.Methods:Joint symptoms and HRQOL were evaluated using an original questionnaire for joint symptoms, the Short Form 36-item Health Survey (SF-36), the EuroQol EQ-5D-3L, and a subscale of the Functional Assessment of Cancer Therapy-Endocrine Symptoms (FACT-ES).Results:Baseline joint symptom and HRQOL data were collected from 330 patients between November 2007 and March 2010. Joint pain and joint stiffness were reported by 61.6 and 59.1 % of patients, respectively, although these symptoms did not affect the activities of daily living in 96.0 and 97.9 % of patients, respectively. Joint pain was reported in the knee by 61.0 % of patients and in the hand by 36.0 % of patients. Joint stiffness mainly affected the hand (67.9 %), especially the proximal interphalangeal joint, and typically occurred upon waking up or in the morning. Most SF-36 domains had good average scores, although slight decreases in physical functioning and role-physical were observed (compared to the national standard scores). The mean EQ-5D utility score was 0.86, and the total FACT-ES subscale score was 62.2/76.Conclusions:After 5 years of anastrozole, many of the patients reported joint pain and stiffness in mainly the hand and knee with mild symptoms and good HRQOL.