The localization of the primary auditory cortex in man was studied by direct recordings in 150 different sites in the superior transverse gyrus, especially in Heschl's gyrus and the planum temporale. The distribution of the primary evoked responses (N13/P17/N26) was studied in 15 epileptic patients who were candidates for surgical treatment. Precise topography of recording sites was determined stereotactically. Our results provide evidence for considering only a restricted portion of Heschl's gyrus (its posteromedial part) as the primary auditory area.