e"> Six isolates of Ralstonia solanacearum causing the bacterial wilt in chrysanthemum (Chrysanthemum sp.) from Lam Dong province and Mekong Delta were isolated and evaluated for infecting to their host. From this result, the isolate of high virulence is selected to serve for identification and further more for research of the disease prevention in the future. This experiment was investigated at the Plant Pathology Laboratory of the Plant Protection Department, College of Agriculture and Applied Biology, Can Tho University from October 2015 to February 2017. The six isolates of R. solanacearum from Ben Tre, Can Tho, Tien Giang, An Giang, Dong Thap, and Lam Dong provinces were used for testing on chrysanthemum that includes BT-176, CT-30, TG-189, AG-57, ĐT-9, LĐ-34. These colonies of those isolates on King's B medium showed with cream white, convex, smooth, and irregular or round, and on triphenyltetrazolium chloride (TZC) medium with pink in the center and fluidal white in the margin. The isolate ĐT-9 was collected in Sa Dec Flower Village of Dong Thap province which displays the highest virulence when it was compared with five other isolates. The 16S rRNA gene sequencing shared the highest similarity values (99%) with R. solanacearum strain KX785160 from the GenBank database causing bacterial wilt on Tongling White Gingerin China.