Using immunohistochemistry, brain natriuretic peptide (BNP)-like immunoreactive (-LI) nerves localize to the anterior segment of the porcine eye. BNP-LI nerve fibers are visualized mainly in the aqueous outflow pathway, ciliary processes and anterior ciliary muscle. A small number of immunoreactive nerve fibers occur in the anterior iris stroma and in relation to the iris muscles and in the cornea. Given the known ocular effects of atrial natriuretic peptide (ANP) and that BNP and ANP seem to share common receptors, these results suggest an ocular role for peptides of this class independent of delivery by the systemic circulation.