The results of psychological testing, EEGs and CT scans were examined for 41 children with congenital or early acquired hemiplegia. On average, IQ was depressed and the magnitude of this depression was highly correlated with lesion size, degree of hemiparesis and EEG abnormality, but not with location of lesion. There were no significant effects of lesion laterality on Verbal vs. Performance IQ on Wechsler tests. However, receptive vocabulary, as measured by the Peabody Picture Vocabulary Test, was differentially depressed by left-hemisphere damage. Further, on a variety of verbal tasks, patients with congenital lesions performed better than those with acquired lesions. In contrast, no significant differences were found between the two groups on spatial tasks.