In the mouse, ADAM3, a well-characterized testis-specific protein of the A disintegrin and metalloprotease (ADAM) family, has a crucial role in fertilization by mediating sperm binding to the egg zona pellucida. However, little is known about ADAM3 in other species, such as domestic pigs. We have identified porcine ADAM3 and analyzed the protein. RT-PCR and trypsinization of sperm surface proteins revealed that porcine ADAM3 is expressed at high levels in the testis and on the sperm surface. Furthermore, an IVF inhibition assay with a recombinant porcine ADAM3 disintegrin domain showed that treatment of the disintegrin domain effectively prevented pig sperm-egg interactions. In the present study, we demonstrated the presence of ADAM3a and ADAM3b molecules in the pig and examined their roles in fertilization.