In four interspecies crossing combinations of grapevine (Seedling 108 x Muscat Hamburg, Muscat Hamburg x Seedling 108, S.V.I8315 x Muscat Hamburg and Muscat Hamburg x S.V.I2375) during three years period, resistance to important fungal diseases agents (Plasmopara viticola and Botrytis cinerea) were examined. Based on results of analysis of variance, for investigated characteristics, components of variance, coefficients of genetic and phenotypic variation and coefficient of heritability in a broader sense were calculated. It was established that for both characteristics and in all crossing combinations, genetic variance took the biggest part in total variability. The lowest coefficients of genetic and phenotypic variation were established for both properties in crossing combination Seedling 108 x Muscat Hamburg. The highest coefficients of genetic and phenotypic variation were determined for leaf resistance to Plasmopara viticola in crossing combination Muscat Hamburg x S.V.I2375, and for bunch resistance to Botrytis cinerea in crossing combination Muscat Hamburg x Seedling 108. Considering all investigated crossing combinations, coefficient of heritability for leaf resistance to Plasmopara viticola was from 87.23% to 94.88%, and for bunch resistance to Botrytis cinerea from 88.04% to 93.32%.