Leptin, the obese gene peptide, is involved in the regulation of feeding behavior and energy balance. Extracellular recordingsweremade fromneurons in slices of the preoptic area/anterior hypothalamus (PO/AH) of rats, to investigate the effects of Leptin on neuronal response characteristics on the level of central temperature controller. Leptin increased dose-dependently tonic activity (firing rate) in all type of PO/AH neurons, but decreased temperature sensitivity (temperature coefficient, TC) in warmsensitive neurons. Our results are step of understanding the complicated mechanisms of action of neuromodulatory acting peptides on the level of central temperature controller – the neurons of the PO/AH.