The presence of neuropeptide Y (NPY) in the brain and retina of gilthead seabream (Sparus aurata L.) was investigated for the first time. For this investigation we employed an immunoperoxidase technique and the western immunoblot analysis using an antiserum raised against porcine NPY. The results showed that NPY-immunoreactivity was widely distributed in the brain of S. aurata. In particular, we have found NPY-immunoreactive (ir) neurons in the area ventralis telencephali pars centralis and pars lateralis, in the area dorsali telencephali pars centralis subdivision two and in nucleus intermedius thalami. An intense NPY-ir was detected in the telencephalon, in the optic tectum, in the thalamus, hypothalamus and in the vagal lobes. Scarce positive fibres were seen in the olfactory bulbs. NPY-ir amacrine cells were observed in the retina. The western immunoblot analysis revealed a protein band with a mobility corresponding to that of synthetic NPY. Our findings are, in general, in agreement with those obtained in other teleosts. The extensive distribution of NPY indicates for this peptide a key role in basic physiological actions, including visual and gustatory inputs processing.