Abstract: Thepolymerase chain reaction (PCR)was successfully employed to develop aspecific assay for plant pathogenic mycoplasmalike organism associated with paulowniawitches'-broom(PWB).A1.2 kb DNA fragment was amplified from DNA extracted fromPWB diseased paulownia tissue culture by PCR. No amplified DNA was detected fromhealthy paulownia sample. Aminimum of only 2.5 pg total nucleic acids from PWB MLO-infected paulownia tissue culture were needed to detect PWB MLO when a 1.2 kb DNA fragment was amplified by PCR.Results showed that DNA amplification by PCR was a highsensitive method in detecting PWB MLO.