Rheological and breadmaking properties of untreated and suboptimally stored wheat samples (grain moisture: 20%, temperature: 20°C) and also of wheat which was inoculated withFusarium spp. were investigated. The deoxynivalenol (DON) content of the stored and inoculated wheat samples ranged between 820-12,000 μg/kg. Gluten proteins were isolated with different extraction solutions and the fractions obtained were analysed by means of RP-HPLC. Microextension tests and micro-baking tests were used for the determination of dough properties (maximum resistance (MR) and extensibility (EX)) and bread volume, respectively. In spite of the extremely high DON concentrations of some wheat samples contaminated withFusarium spp. they showed only a slight decrease of the amount of gluten proteins. Extension tests of dough led to a slight decrease of MR, bread volumes stayed almost the same compared with the non-contaminated grain. The contamination of wheat withAspergillus andPenicillium led to a high decrease of gluten proteins, which resulted in an extremely decreased MR of the dough and a very low bread volume.