A case is reported of anaphylactoid reaction to atracurium, used for the induetion of an- esthesia for skin graft in a 36 year old man. The patient had no previous history of any allergic tendency. It is not possible to distinguish between direct pharmacological effects and immune mediated hypersensitivity reactions by clinical observation alone. The mechanism of reaction in this patient was investigated by the leukocyte histamine release test, intradermal test, direct intravenous challenge with other induction agents used during the induction of anesthesia and radioallergosorbent test. The histamine releasing property of atracurium, the distinguishing methods between ana phylactic and anaphylatoid reaction, and the anesthetic management for this kind of reaction are discussed.