Severe Broca aphasia and left hemiplegia without right limb apraxia occurred suddenly in a right-handed man with no personal or family history of left-handedness. Postmortem examination showed infarction of the right hemisphere, limited almost entirely to the precentral gyrus. In this patient, cerebral dominance for speech lay in the right hemisphere, but dominance for limb praxis lay in the left. This case provides evidence that cerebral dominance for speech and handedness in dextrals may be dissociated. It also suggests that lesions of the precentral gyrus are of major importance in producing Broca aphasia.