After over 10 years of negotiations there still remain unresolved issues of great importance, which the Caspian coastal states could not agree upon. Unsettled are vital issues of the extension of national sovereignty and problems of the future borders of Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan in Caspian Sea, as well as not less sensitive issues of the right on the exploration and exploitation of the Caspian natural resources, especially oil and gas. The greatest obstacle to the negotiation process of the clarifying the legal status of the Caspian Sea comes from the often-conflicting interests of the Caspian littoral states. A successful interstate dialogue and legal compromise accepted by all the littoral states has been achieved only on the fragile Caspian environment through signature of Framework Convention for the Protection of the Marine Environment of the Caspian Sea. May it be the first positive sign for the future progress in the ongoing negotiations.