Abstract: The causal agent of grape black rot, Guignardia bidwellii, is not a subject of muchinterest in Europe and little scientific literature on it is available. Identification was and still isbased on symptoms, more seldom also on the fungus morphology by microscopic observation.We present here a preliminary report on its characterisation by molecular and proteomic methods,which indicates the existence of two distinct taxa, isolated from Vitis resp. Parthenocissus hostplants. Furthermore, a microsatellite analysis of G. bidwellii on DNA extracted from grapeberries and leaves showing symptoms of black rot, collected from several European populations,showed that berry and leave symptoms derive from the same basic inoculum. However, the 12collections made at different sites and years could be separated into 4 four populations.