Carbonate terranes provide some of the most difficult areas in the world in which to identify ground water regimes. The US/IHD Work Group on the Hydrology of Carbonate Terranes, recognizing the difficulties, makes five recommendations in its final report to the U.S. National Committee. These are (1) improve the scientific education of hydrogeologists; (2) intensify research, particularly concerning the chemistry of water/carbonate relationships; (3) develop new and improved exploration and drilling techniques; (4) identify some institution to become a center for information concerning the hydrology of carbonate terranes; and (5) establish a committee to provide an overview, assess progress, and suggest needed activities.