Ghrelin is a novel growth hormone-releasing peptide originally identified in the rat stomach as an endogenous ligand of the growth hormone (GH) secretagogue receptor. Recent work suggests that ghrelin plays an important role in reproductive function. In this study, prepubertal pig ovaries were used to examine ghrelin levels in the ovarian follicles. Ghrelin levels in the follicular fluid, follicular wall and culture medium were measured using an enzyme immunoassay (EIA). The ghrelin level in the follicular fluid (18 pg/ml) was the sum of the amounts found in the follicular wall (13.7 pg/ml) and the culture medium (4.6 pg/ml). In conclusion, the data presented in this paper suggest local production of this hormone in ovarian follicles.