An ADAM is a transmembrane protein that contains a disintegrin and metalloprotease domain and, therefore, it potentially has both cell adhesion and protease activities. Currently, the ADAM gene family has 29 members, although the function of most ADAM gene products is unknown. We discuss the ADAM gene products with known functions that act in a highly diverse set of biological processes, including fertilization, neurogenesis, myogenesis, embryonic TGF-alpha release and the inflammatory response.