A nearly homogeneous water mass, the Norwegian Sea Deep Water, is found below 2000-m depth in the Norwegian and Lofoten basins of the Norwegian Sea. Recent observations indicate that this water is a mixture of relatively cold and fresh Greenland Sea Deep Water with warmer, saltier Eurasian Basin Deep Water from the Arctic Ocean. We have found this mixture along the western and southern periphery of the Greenland Sea, near the level where the pressure-compensated densities of the parent water masses are equal. The along-isopycnal mixing produces a remarkably uniform water mass, which can be traced only a short distance away from its entry into the Norwegian Sea through gaps in the mid-ocean ridge north of Jan Mayen Island. Direct measurements of flow through these gaps confirm motion in the proper sense to accomplish this connection. ¿ American Geophysical Union 1988