Erysiphe pisi causes powdery mildew disease in garden pea. It is a biotrophic ascomycete member necessitating a living host for its survival. An attempt to identify the global proteome of E. pisi pathogen is made using a sensitive and reliable nano LC-MS/MS approach. The protein profiling of two isolates of E. pisi; Ep01 and Ep02 varying for virulence upon testing on a commercial cultivar, Arkel led to the detection of a total of 211 and 214 distinct proteins in Ep01 and Ep03 isolates respectively. In addition, a total of 203 and 207proteins from Ep01 and Ep03 isolates respectively were found to be hypothetical or proteins with not yet predicted functions based on GO (biological process). The protein accessions detected in these isolates were categorized into functional protein classes with some of the identified proteins reported to be involved in pathogenesis or virulence. The proteins belonging to the functional classes like stress related, signal transduction and secondary metabolite formation might be involved in virulence and pathogenesis. The proteome proposed in this study would serve as a reference proteome to facilitate the understanding of the functional aspects of an obligate biotrophic fungal pathogen.