In this article, the author explains that UNESCO has been concerned by the problem of protection of underwater cultural heritage since its early days, He emphasizes the fact that apart from two very general provisions in the 1982 U.N. Convention on the Law of the Sea, there is no international legal instrument dealing with this very international topic, There is however a greater concern from the scientific and archaeologist community and a vast majority of States have now recognized that the matter should be regulated at international level, The author describes the various interests, the past, present and possible future steps to elaborate such an international legal instrument and the current difficulties encountered. Several official UNESCO documents are attached as annexes, such as a preliminary study officially addressed to the UNESCO Member States in 1995. Copyright (C) 1996 Elsevier Science Ltd.