Updated project metadata. Clubroot of Brassicaceae, an economically important soil borne disease, is caused by Plasmodiophora brassicae Woronin, an obligate, biotrophic protist. This disease poses a serious threat to canola and related crops in Canada and around the globe causing significant loss to seed yield. The pathogen is continuously evolving and new pathotypes are emerging, this necessitates the development of novel resistant canola cultivars to manage the disease effectively. Given that proteins play a crucial role in majority of biological processes and molecular functions, the identification of differentially abundant proteins (DAP) using proteomics information is an attractive approach to understand the plant-pathogen interactions as well as in the future development of gene specific markers for developing clubroot resistant (CR) cultivars. In this study, P. brassicae pathotype 3 (P3H) was used to challenge CR and clubroot susceptible (CS) canola lines. Root samples were collected at three distinct stages of pathogenesis, 7-, 14-, and 21-days post inoculation (DPI), protein samples were isolated, digested with trypsin and subjected to LC-MS/MS analysis. A total of 937 proteins demonstrated a significant (q < 0.05) change in abundance in at least in one of the time points when compared between control and inoculated CR-parent, CR-progeny, CS-parent, CS-progeny and 784 proteins were significantly (q < 0.05) changed in abundance in at least in one of the time points when compared between the inoculated- CR and CS root proteomes of parent and progeny across the three time points tested. Functional annotation of the differentially abundant proteins (DAPs) revealed several proteins related to calcium dependent signaling pathways in response to the pathogen. In addition, proteins related to reactive oxygen species (ROS) biochemistry, dehydrins, lignin, thaumatin, and phytohormones were identified. Among the DAPs, 74 putative proteins orthologous to CR proteins and quantitative trait loci (QTL) associated with eight CR loci in four chromosomes including chromosomes A3 and A8 were identified. In conclusion, these results have contributed to an improved understanding of the mechanisms that are involved in mediating response to P. brassicae in canola at the protein level.