On wheat seeds harvested in Upper Silesia (south-western Poland) a large number of species of Fusarium were recorded. Fusarium avenaceum and F. culmorum were most commonly isolated. Flooding of fields for 1-7 days caused the increase of pathogenic Fusarium spp. in seed samples, especially F. culmorum. The infection of seeds caused a rapid decrease of their viability, and negatively affected health status of emerging seedlings in field conditions, in spite of performed chemical treatment.