Contribution of coho salmon (Oncorhynchus kisutch) produced by river systems entering Puget Sound, Washington, to the commercial troll fishery off the coasts of Washington and Vancouver Island in 1953 was estimated using the recoveries of fin-marked salmon. A commercial fishery in Puget Sound was used as a sampling tool. The production area was defined by the percentage exploitation by the Puget Sound fishery of runs of coho salmon to river systems in the Puget Sound area. Puget Sound streams as defined produced about 9% of the coho troll fishery catch off Washington and Vancouver Island in 1953. Major limitation of this study was the degree of accuracy in defining the production area.