After 30 years of negotiations, the Rhine river is still very polluted. Although the concentration of some pollutants has diminished during the past few years, the quantity of other harmful substances is still increasing. This lack of progress can be explained to a large extent by a set of peculiar circumstances which seems to be unique for the Rhine. The most important of these circumstances is the international dimension of the situation. The main stem of the Rhine flows through the sovereign territories of Switzerland, the Federal Republic of Germany, France and the Netherlands. Its drainage area, moreover, also covers Italy, Austria, Luxemburg and Belgium. Obviously, no anti-pollution policy can hope to be effective until at least the most directly concerned of these eight States have reached agreement on common objectives and common measures. Reaching agreement, however, is complicated by the problem of conflicting uses which may be more intricate for the Rhine than for any other international river.