Chinook salmon Oncorhynchus tshawytscha support important subsistence and commercial fisheries throughout the Yukon River. Low returns and diverse user groups have made management of these fisheries contentious and have necessitated information on the origin of the spawning migration and harvest. Here we compare estimates of individual assignment and stock composition derived from genetic and radiotelemetry data collected from the same Chinook salmon. Radiotelemetry and genetic individual assignments were highly concordant. Agreement between methods for individual assignment was 79% to region and 93% to country when using the most probable genetic criterion, improving to 94% for region and 98% for country when using the ≥95% probability genetic criterion; however, under the more stringent criterion, fewer individuals could be assigned. Further analysis showed that estimates of stock composition based on radiotelemetry and genetic methods were within 6% of each other and were not significantly different. The concordance between estimates of individual assignment and stock composition from the radiotelemetry and genetic methods indicates that both methods are credible tools for fishery assessment of Yukon River Chinook salmon. Received October 14, 2011; accepted April 17, 2012