The author states that most psychiatrists should be able easily to recognize tardive dyskinesia. However, this disorder is a subset of a large variety of abnormal involuntary movements, some of which may resemble tardive dyskinesia. Others have serious implications if they are misdiagnosed as tardive dyskinesia. The author describes the characteristic features of a wide variety of abnormal involuntary movements, including parkinsonism, the dystonias, choreas and choreoathetosis, tremors, tics, stereotypies and mannerisms, oral-facial dyskinesias, and disorders with varied or complex manifestations. He emphasizes the differential diagnosis of tardive dyskinesia.