The presence and phylogenetic position of endosymbiotic bacteria were studied from the pine needle gall midge, Thecodiplosis japonensis that is the most serious insect pest of the red pine, Pinus densif lora. PCR amplification using the general primers for eubacterial16S ribosomal DNA (rDNA) and the sequence of the amplified product showed that T. japonensis harbours the obligate intracellular bacteria Wolbachia, which has been known to infect an extremely wide range of insect species, in which it induces reproductive alterations. Phylogenetic analysis of Wolbachia strain of T. japonensis based on the sequences of 16S rDNA and ftsZ gene show agreement, indicating that this bacterium belongs to A-subdivision of Wolbachia.