Three subterranean asellid isopods from Greece are described: Proasellus ambracicus n.sp. from phreatic waters of Epirus, Proasellus minoicus n.sp. and Proasellus cretensis n.sp. from phreatic systems of the island of Crete. The existence of subterranean species of Proasellus in the island of Crete is correlated with the unstableness of the surface aquatic systems which were the cause of the colonization of the hypogean aquatic biotopes.