Travel time of adult sockeye salmon (Oncorhynchus nerka) through the Karluk River, Alaska, was determined from fish tagged with Petersen disks about 2 miles (3 km) inside the river mouth and timed as they reached a weir at Karluk Lake, 21 miles (34 km) upstream. Migration time to the weir averaged 7 days for spring run and l0 days for fall run fish. The influence of three factors on travel time was determined by multiple regression analysis. Most important was time of season, followed by number of fish and rainfall.