Recently, oceans and soils have been explored for their large unknown microbial genomic resources, insects could prove another avenue for genomic innovations as majority of insects are known to harbor the symbionts. The objective of this work was to estimate the microbial diversity associated with the Hessian fly using 454 pyrosequencing. Insect fat body and midguts from three different larval stages were dissected out. Following DNA extraction, the V3, the most hypervariable region (corresponding to positions 341-534 in E. coli) of the 16S rRNA gene was amplified and sequenced. These 454 tag sequences (total of ~6000) serve as query against reference database (V3RefDB) and the phylotype assignments were made according to V3RefDB sequences that display the minimum distance to the query. The most abundant group associated with Hessian fly is &gamma-Proteobacteria followed by &beta-Proteobacteria and Bacteroidetes. For assignment of similarity based operational taxonomic units (OTUs), sequences were aligned and distance matrices were calculated by using ARB software, and clustering was done by DOTUR. At the lowest level of dissimilarity, a total of 951 OTUs were recorded. A relatively large number of different populations dominate all samples, which count for observed phylogenetic diversity.