Twelve Polish spring wheat cultivars and 18 spring wheat accessions from CIMMYT, Mexico, were examined for resistance to a highly pathogenic Fusarium culmorum strain KF846 and powdery mildew in 5-year field experiments. Resistant wheat cultivars (Sumai 3 and Frontana) served as controls. The mean percentage of Fusarium-damaged kernels (% FDK) for 5 years was lower in CIMMYT accessions (16.7%) than in Polish spring cultivars (28.3%). In all Polish spring cultivars, % FDK was higher than in the control cultivars Sumai 3 and Frontana (12-20%). The mean disease score (on a scale of 1-9) for powdery mildew (natural infection) for all examined cultivars and lines ranged from 0 to 7 and in the Polish spring cultivars was significantly lower (0-5). Cultivars Eta, Henika, Ismena, Jasna and Olimpia were found to be the least susceptible to powdery mildew in field experiments. The laboratory host-pathogen tests with Blumeria graminis f. sp. tritici isolates showed that only two cultivars were characterized by identical resistance patterns as the standard differential lines with documented resistance genes. Cultivar Alkora had the gene Pm3d, and Henika had Pm5. The gene Pm3d was identified in cultivars Jasna and Eta in combination with another unknown gene/genes. Cultivars Santa and Torka had the gene Pm5 in combination with another unknown gene/genes. Four cultivars: Banti, Ismena, Olimpia and Sigma, showed resistance to all mildew isolates employed in a laboratory test. The accession IPG-SW-14 was the least susceptible to both pathogens (F. culmorum and powdery mildew) in all 5 years of experiments. This line is the best candidate for deriving new cultivars with improved resistance to fungal diseases.