Antibodies blocking the calcitonin gene-related peptide have revolutionized episodic and chronic migraine treatment. However, their applicability to non-cephalic pain conditions, such as osteoarthritis, is yet unknown. Osteoarthritis remains a clinical challenge, associated with high disability and limited treatment options. Like migraine, neuropeptides including calcitonin gene-related peptides are involved in its pathophysiology. We present the first case of a patient: a 73-year-old female with osteoarthritis who received monthly treatment for her chronic migraine with 140 mg subcutaneous erenumab, a monoclonal antibody against the receptor of calcitonin gene-related peptide. Though the migraine was unresponsive, the patient's arthritic symptoms improved drastically during treatment period with erenumab; daily pain decreased from VAS 7 to 2, and walking distance doubled from 1,000 m to 2,000 m. The arthritic symptoms relapsed after discontinuation of erenumab. Erenumab could potentially have beneficial effects on symptoms of osteoarthritis. Future studies investigating these effects are warranted.