Two cases with the mildest form of Broca's aphasia were studied neuropshychologically and neurologically. In case 1, a 58-year-old right-handed man had dysarthria, literal paraphasia, and literal paragraphia because of development of glioma. Comprehension was excellent. There were the right central and hypoglossal paresis and abolition of gag reflex. The site of lesion confirmed by computerized tomography and operation was in the lower part of the left precentral gyrus. A month after the resection of the tumor, only paragraphia improved. In case 2, a 58-year-old right-handed man developed the essentially same neurological and linguistic symptoms as those of case 1. Computerized tomography demonstrated a small hematoma probably restricted in the left inferior precentral gyrus. Three months later, the symptoms subsided except for slight dysarthria and dysgraphia. On the basis of literature and our two cases, it may be concluded that the left inferior precentral gyrus plays an important role not only in articulation but also in writing, and that this area is a more critical zone for Broca's aphasia than the foot of the left third frontal gyrus.