Stereotypies are patterned, repetitive, purposeless movements that are performed the same way each time. They are commonly seen in individuals with autism, schizophrenia, or mental retardation, and also occur as a feature of tardive dyskinesia and as movements in those with akathisia. We studied 10 children who had stereotypies but were not autistic or mentally retarded. Although most had an uneventful delivery, seven had mild to moderately delayed developmental milestones. Five had hyperactive behavior or attention-deficit problems. All appeared to be of normal intelligence. The median age of onset of stereotypies was 12 months. The stereotypies included arm flapping, arm and hand posturing, finger wiggling, body rocking, leg shaking, facial grimacing, involuntary noises, neck extension, and eye blinking. Of the 10 children, only two stopped having stereotypies eventually without medications.