Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis has been reported in Graves' disease patients treated with antithyroid drugs (ATDs), especially propylthiouracil. ATD-induced ANCA-associated vasculitis usually involved the kidneys followed by the respiratory organs and skin. The treatment of ANCA-associated vasculitis induced by ATDs is to stop ATD therapy immediately, which often leads to an overall good prognosis. We report a case of ANCA-associated vasculitis in the peripheral nerves of the lower extremities in a 66-year-old woman who was treated with methimazole (MMI) for Graves' disease. To our knowledge, this is the third case of peripheral nervous system (PNS) involvement of ATD-induced vasculitis and the first case of PNS vasculitis associated with MMI.