A novel oomycete root pathogen has been identified and characterized, Pythium brassicum P1. It only attacks plant species belonging to brassicaceae family causing root necrosis, stunting and yield loss. Since P. brassicum P1 is limited in host range, this prompted us to sequence the whole genome and compare it to those of broad host range Pythium species. The assembled sequencing data yielded a total genome size of 50.3Mb contained in 5,434 scaffolds, N50 of 30.2 Kb, 61.2% G+C content, and 13,232 putative protein-coding genes. A comprehensive annotation has been performed further to identify functional classes, pathogenesis-related genes, secretome, synteny analysis, identification of carbohydrate-active enzymes, candidate effectors, and identification of over- and under-represented families, etc.