Abnormalities in neural transmission of dopamine play an important role in development of schizophrenia. Dopamine 1 (D1)-like receptors in 16 areas of the cerebral cortex were measured in the postmortem brains of 13 schizophrenics and 10 controls, using [3H]SCH23390 as a ligand for receptor binding. The specific [3H]SCH23390 bindings were statistically significantly increased in the medial and inferior cortex (Brodmann Area (BA) 20 & 21) and superior parietal cortex (BA 7) of schizophrenic patients, compared to those of the controls. The increases were also marked in the cerebral cortices of off-drug cases of patients with schizophrenia, who had not received antipsychotic drugs for more than 40 days before death. These results suggest that there are changes in dopaminergic transmission through the D1 receptors in the parieto-temporal cortex of schizophrenia, and that the altered functions are involved in the pathophysiology of the disease.