We evaluated 11 patients with hemiparkinson-hemiatrophy syndrome, 6 with body and contralateral cerebral hemispheric hemiatrophy, 4 with only body hemiatrophy, and 1 with just brain hemiatrophy. The mean age of symptom onset was 38.1 years (range, 18 to 54) with 5.2 +/- 3.1 (mean +/- SD) years of illness until the last follow-up visit. The presenting symptom was unilateral tremor in 6 patients, hand dystonia in 2, bradykinesia in 2, and abnormal gait in 1 patient. Three patients had a good response to levodopa, 4 had moderate response, and 2 patients had a poor response. During a mean follow-up period of 1.7 years (range, 4 months to 5 years), the Hoehn and Yahr score changed in only 3 patients: 2 gained 1.5 points and 1 gained 3 points over 2.5 years. We discuss the association between hemiparkinsonism-body hemiatrophy and contralateral hemispheric hemiatrophy, and raise the possibility of early childhood brain insult with delayed-onset parkinsonism.