Fusarium crookwellense was isolated for the first time in Japan from scabby wheat harvested in Hokkaido in 1991. Four isolates were obtained and examined for their mycological features on culture media, mycotoxin production, and pathogenicity to wheat and barley. The texture of fungal colonies and the morphology of macroconidia on a potato dextrose agar medium were similar to those of Fusarium graminearum. All F. crookwellense isolates examined produced nivalenol, 4-acetylnivalenol, and zearalenone on rice media at levels ranging from 0.9 to 22.5 μg/g, 0.5 to 25.0 μg/g, and 1.4 to 162.5 μg/g, respectively. All were pathogenic toward the wheat and barley strains tested, and scab symptoms were found on the heads and leaves of plants. This is the first report on domestic isolates of F. crookwellense from the crop field in Japan. © 1994, Mycological Society of Japan. All rights reserved.