Obestatin is a recently discovered 23 amino acids peptide derived from the ghrelin gene. As opposed to ghrelin, obestatin was shown to inhibit food intake in mice. The aims of this research were to study the effects of acute obestatin treatment on feeding behavior in the rat and its effects on GH and corticosterone secretion. Our results demonstrate that in young-adult male rats, obestatin effectively blunts the hunger caused by short-term starvation. Obestatin did not modify GH secretion in 10-day-old rats and did not antagonize the GH-releasing effects of hexarelin. Moreover, obestatin administration had no effects on spontaneous corticosterone secretion. In conclusion, these data demonstrate that in young-adult male rats the newly discovered obestatin can inhibit feeding but does not modify GH and corticosterone release in infant rats.