The environmental problems of today have more and more border-crossing character. In the present paper the ecological problems of the german-polish border region of the Odra estuary, which form a border crossing ecological sensible unit, were studied for special parts of environmental protection, nature protection and water management regarding the quality of internal and external coastel waters, international conventions for protection of the Baltic Sea, cooperation in the field of protection and management of groundwater and waste water. A critical summarized evaluation based on the analysis was established which helps identifing the defizits and possibilities for progess of the bilateral cooperation and which indicate precise focal points for border-crossing fields of actions in the region of Odraestuary, to ensure a sustainable and continuing developpement of this region.