Sunflower is attacked by several pathogens that reduce both the quantity and quality of harvested grains. It is necessary to keep evaluating the germplasm of this oil crop in order to detect new resistance sources to be included in breeding programs. Different accessions from North Central Regional Plant Introduction Office, Ames, IA, were evaluated for reaction to A. tragopogonis and S. sclerotiorum infections on levaes and capitula, respectively. Under our conditions, statistical analysis showed differential responses to white rust severity, white rot incidence and relative incubation period. Accessions were classified according to their level of resistance to each infection type. A general and favorable association between white rust and white rot performances was absent in the evaluated genetic material. The accession PI 343790 had the highest level of resistance to each quantified variable while the accessions Ames 3224, Ames 4040 and Ames 4050 had the lowest levels of resistance. Applicability of these results in sunflower genetic improvement for resistance to the studied diseases is discussed.