We have analysed the aphasia profiles of 19 cases with subcortical infarction or haemorrhage. Several components of the aphasic syndromes, especially sentence length and grammatical form (together compromising fluency), ease of speech initiation, articulation, voice volume, and auditory comprehension, were individually isolated for correlation with CT lesion site. Each component had a specific lesion site correlation, and lesions in various deep periventricular white matter regions were the critical ones for all components of aphasia. Simple tabulation of lesions as cortical or subcortical, and restricting analysis to lesions of basal ganglia would both have proved inadequate to account for clinical findings. A review of 61 subcortical cases in the neurological literature for which CT and aphasia data were available supports these conclusions.