Twenty-nine isolates of Discula destructiva Redlin from the Pacific northwestern United States and British Columbia, Canada were extracted for the presence of double-stranded RNA by use of phenol-chloroform and CF-11 chromatography, Seven/29 were positive. Agarose-gel banding profiles of the western isolates were different from those found previously in 80/80 isolates from the eastern U.S. These results suggest that isolates of D. destructiva responsible for dogwood anthracnose in Washington, Oregon, Idaho, and British Columbia may have an origin different from that of the eastern isolates.