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Oat (Avena sativa L.) is a crop grown for feed and for food industry. It is the most used fodder plant after barley in Finland and is also exported. In 2011, oat was grown on 308 200 hectares in Finland and the average yield per hectare was 3390 kg. Several fungal and virus diseases cause remarkable crop losses in oats. Especially in the temperate zone, the most common disease is the head blight caused by Fusarium species. These fungi overwinter as mycelium or spores and produce mycotoxins. In Finland, F. culmorum is a common DON toxin producer and F. langsethiae is a T-2/HT-2 toxin producer in oats. Toxins affect the quality of oat yield and can make it unsuitable for use. Therefore, the amounts of mycotoxin allowed in cereals are stipulated by food safety authorities. This thesis was a part of MTT Agrifood Research Finland's Hyötygeeni project. The aim of the research was to study resistance of eight oat cultivars to F. culmorum and F. langsethiae. Indicators of resistance were germination of the infested seeds, the proportion of infected seeds and the amounts of mycotoxins. The trials were made in greenhouse with artificial inoculations.The results indicated that four cultivars expressed similar levels of resistance to both Fusarium species. Three cultivars had better resistance to F. langsethiae than F. culmorum and only one cultivar had better resistance to F. culmorum than F. langsethiae. In future research, the results can be utilized in resistance breeding. Global warming will increase the risk of plant diseases. On that account importance of breeding will be emphasized.