Methimazole-induced agranulocytosis is a rare, but critical side effect that should be recognized as soon as possible since it may induce a life-threatening condition when it was overlooked. Histiocytic necrotizing lymphadenitis is also called Kikuchi's lymphadenitis, and this is a rare form of lymphadenitis with a self-limited clinical course and this illness is accompanied by cervical lymph node enlargement, fever and malaise. We recently experienced a patient with methimazole-induced agranulocytosis and Graves' disease, and this was accompanied by Kikuchi's disease; the patient presented with sore throat and multiple enlarged cervical lymph nodes. To the best of our knowledge, there is no previous report on methimazole-induced agranulocytosis combined with Kikuchi's disease. Therefore, we report here on this very rare case along with a brief review of the relevant literature.