Periwinkle (Catharanthus roseus (L.) G. Don) blight caused by Phytophthora parasitica Dastur is a serious and wide-spreaded soil-borne disease in Taiwan. Root and stem rots were also observed frequently in humid conditions. Burkholderia gladioli was isolated and identified to be antagonistic to P. parasitica. B. gladioli could not only suppress the growth of P. parasitica in vitro, but decrease the rate of disease development in periwinkles. The hyphae of P. parasitica were collapsed by B. gladioli on the cultural medium. Plant height, fresh weight and the percentage of periwinkle seedling survived were significantly (P=0.05) higher in those treatments applied with B. gladioli compared with the non-treated control.