Experiment on pathogenicity of Phytophthora  colocasiae causing taro leaf blight disease was carried out under net house condition of thr Department of Plant protction, College pf Agricultural and Applied Biology, Can Tho University at the aims to find out the highest pathigenic isilate of Phythophthora colocasiae. Results showed that among four isolates of Phythophra colocasiae including PCTV1, PCTV2, PVST and PCĐT, the isilate PCTV1 caused highest disease in tari which disease incidence and severity were 47.71% and 38.79%, respectively.