The United Nations Convention on the Law of the Sea contains the global framework necessary for the protection and preservation of the marine environment and the development of its resources. Like all treaties, the Convention cannot work unless a sufficient number of States become Parties to it. Moreover, becoming a Party to the agreement is only the beginning: the Convention has to be implemented in order to work. Implementation for a State includes: formulation of a consistent national marine policy; enactment of national legislation; taking national, regional and global institutional measures; undertaking subregional, regional and global co-operation. Very few Mediterranean States have ratified the Convention so far. Fortunately, participation in the Mediterranean Action Plan, and specifically in the Barcelona Convention and its four Protocols, is extensive. But ratifications of the Protocols on Land-based Sources of Pollution and on Specially Protected Areas are still due by some States. National implementation of these instruments is also slow and yet the health of the Mediterranean Sea depends on such action. Mediterranean States have been leaders in protecting the marine environment. The Mediterranean Action Plan, by assisting in the regional implementation of the Law of the Sea Convention, has done a great deal to promote the effectiveness of the global constitution. However, the progress made so far needs to be consolidated through increased national commitment and action, so that new endeavours to protect and preserve the Mediterranean marine environment may be undertaken with confidence.