It has been suggested that NLO or BLO infectious agents are related to TPD of Hevea. In order to characterize the prokaryotic organisms and establish a detection method, a novel method was developed to amplify the prokaryotic 16SrDNA. According to the conservative regions of the 16SrDNA sequences of the known MLOs, a pair of degenerate primers were designed and synthesized for polymerase chain reaction (PCR). The total DNA used as the template for PCR were extracted from the bark of healthy and diseased Hevea trees, respectively, and the PCR reactions were carried out at 94 C- denaturing for 30 secs, 58 C- annealing for 1 min. and 72 C- elongating for 2 min. After 30 cycles amplification, the products were subjected to 1;agarose gel electrophoresis. The results showed that all of the TPD affected samples gave a band approximately 865bp in length, while the healthy ones gave none. This result further demonstrated that NLOs or BLOs are closely related to TPD of Hevea, which supports our previous work involving electron microscopy, grafting and an effective therapy using tetracyclines. Cloning and sequencing of the amplified PCR products is being carried out and, subsequently, work to search for available regions and the generation of oligonucleotide probes and specific PCR primers. The molecular diagnostic technique for TPD of Hevea can be expected to be developed in the future.