Fusarium spp. are widely spread fungal pathogens with a huge plant host range. Fusarioses belong to the most important agents causing economic damage on maize by yield loss but mainly by polluting the grains with mycotoxins. These mycotoxins represent a threat for both human beings and animals when ending up in the food chain. The worldwide most commonly found mycotoxins are deoxynivalenol (DON), zearalenone (ZON) and fumonisins (FUM). The ideal circumstances for a contamination by Fusarium are given by a warm temperature range and humid weather conditions. Variation in those climatic conditions causes a strong year by year variation of the average contamination of the harvest with mycotoxins. In addition, various Fusarium species are predominant in different climatic areas, developing specific mycotoxins. In recent years, a shift in favor of thermophilic Fusarium species could be observed. In order to get an overview of these changes, an accurate determination of Fusarium species is required. In this master thesis, 1210 maize crops from 25 locations in three climatic regions (Northern Wetlands, Illyricum and Pannonicum) in Austria were analyzed. Using morphological and molecular biological methods to identify the Fusarium species. The very dry and hot weather conditions in 2013 led to a domination of the Liseola section containing F. subglutinans (24%), F. proliferatum (37%) und F. verticillioides (13%). A relation between the occurrence of Fusarium and weather conditions can also be observed in Austria. The amount of Fusarium species is significantly higher within the Illyricum and the Northern Wetlands as in the dry situated pannonical area. The results show that in addition to DON and ZON, FUM could also gain importance. Whether the climate is the cause for the shift observed to Fusarium spp of the Liseola section, needs to be further investigated.