A new system for the detection of phytoplasmas in both rice and mulberry plants using PCR assay and laser stylectomy was investigated. Pure phloem sap was collected in a capillary tube from plants with phytoplasma diseases using laser stylectomy (insect laser technique). Direct detection of phytoplasmas in the phloem sap was attempted using the polymerase chain reaction (PCR). The phloem sap was heated at 95°C for 5 min or not heated. and used directly as the DNA template for PCR amplification. Two sets of oligonucleotide primer pairs were used to amplify the target DNA fragment (length, 1.37 kb and 0.75 kb) from 16S rRNA genes of phytoplasma. The predicted band was observed for almost all the heated or unheated samples collected from diseased plants, whereas no band was detected in the samples collected from healthy plants. Each of the amplified PCR products was found to be the target DNA from 16S rRNA genes of phytoplasmas based on the analysic of their restriction enzyme digestion and determination of the DNA sequence. Thus, the new detection system using both laser stylectomy and PCR assay was found to be sensitive and specific.