The case of a right-handed patient who suffered aphasic symptoms from a right hemisphere tumor is described. A summary of such cases from the literature, made by Ettlinger, Jackson, and Zangwill, is also presented and brought up to date. We are inclined to discount their explanation of such symptoms as being due to a familial tendency to left-handedness. Instead, we propose the following hypothesis Aphasic symptoms may occur as a result of destruction of cortical areas of the left hemisphere or of subcortical nuclei in the right hemisphere. Transient aphasia may occur from injury to either hemisphere, and finally, certain left-handed persons may constitute exceptions to these rules.