Erdheim-Chester disease is rare form of non-Langerhans cell histiocytosis characterized by organ infiltration of CD68+ CD1a− histiocytes. Between 500 and 600 cases have been reported. It is a multifaceted disease ranging from a solely asymptomatic bone to a fatal multisystem pattern. Bone involvement occurs in more than 90% of cases. Although not life-threatening, bone localizations can be responsible of difficult-to-treat pain and disability. Treatment depends on lesion severity. Bisphosphonates have been reported to be efficient and safe in bone involvement. We report a case of a biopsy proven bone Erdheim-Chester disease in a 65-year-old woman with history of breast cancer. Her pain was relieved after 3 perfusions of zoledronic acid and the efficiency remained at one year of follow-up.