There is some evidence of specific oro-detection of free fatty acids (FFA) in rodents and humans. The aim of this study was to record gustatory evoked potentials (GEPs) in response to FFA solutions, and to compare GEPs in response to linoleic acid solution with GEPs obtained after stimulation with sweet and salty tastants. Eighteen healthy men were randomly stimulated with fatty (linoleic acid), sweet (sucrose) and salty (NaCl) solutions, at two concentrations in the first experiment. Control recordings (n=14) were obtained during stimulation by a paraffin oil mixture without FFA or by water. In the second experiment, eighteen men were randomly stimulated with 5 FFA solutions and a paraffine emulsion. GEPs were recorded with EEG electrodes at Cz, Fz, Pz. GEPs were observed in response to FFA in all participants. GEP characteristics did not differ according to the quality and the concentration of the solutions in the first experiment, and according to the FFA in the second experiment. This study described for the first time GEPs in response to FFA and demonstrated that the presence of FFA in mouth triggers an activation of the gustatory cortex. These data reinforce the concept that fat taste could be the sixth primary taste.