One or more types of hallucinations were experienced by 96 out of a group of 458 cases of supratentorial brain tumor. Formed auditory hallucinations were related predominantly to temporal lobe lesions, though the frontal and parietal were also involved. Unformed auditory hallucinations were related predominantly to frontal and temporal lesions, though all the lobes were involved as well as midline lesions notably the pituitary: in lobe lesions the hallucinations were usually on the side of the lesion. Although pure occipital lobe lesions gave rise to only visual hallucinations, either formed or unformed or xanthopsia, formed and unformed visual hallucinations were related to lesions in all the lobes of the brain in almost equal distribution, the temporal showing a slight predominance. Xanthopsia seemed related to occipital lobe lesions. Olfactory hallucinations were related to lobe lesions throughout the entire brain, though mainly to the temporal, with frontal and parietal next in descending order. Tactile hallucinations appeared with lesions of the frontal, parietal and temporal lobes. Although the panietal lobe gave rise to the widest variety of types of hallucinations, pure parietal lobe lesions gave rise to a relatively high incidence of tactile hallucinations. Gustatory hallucinations tended to appear together with olfactory hallucinations and to be related to temporal lobe lesions. It was noted that the temporal was the lobe most frequently involved by all tumors, and that the panietal and temporal are the two centrally located lobes in the brain. The occipital lobe seemed most restricted to only visual hallucinations. Though there are tendencies for certain types of hallucinations to be predominantly related to certain lobes of the brain, these hallucinations also tend to be caused by adjacent or distant lobes.Abstract Teaser