The composition of bacterial community in the intestine of the white shrimp, Litopenaeus vannamei under laboratory culture condition was determined using the 16S rDNA clone library. 16s rRNA gene was amplified and a library was constructed by using the genomic DNA extracted from the bacteria in the shrimp intestine as template. 12 different RFLP patterns of the clones were obtained by restriction fragment length polymorphism analysis using AfaⅠ and MspⅠ. Compared with the published sequences in GenBank database, sequencing results of cloned 16S rDNA amplicons revealed a diverse community including γ-proteobacteria and Firmicutes in the intestine of artificial diet-fed shrimp. Results showed that the Firmicutes group can be a dominant component (75.4%) in the shrimp intestinal microflora and other clones belong to γ-proteobacteria (24.6%) which were identified as Shewanella sp., Pantoea sp., Aranicola sp., Pseudomonas sp. and Vibrio sp., respectively. These results provide the first comprehensive description of microbial diversity of the white shrimp intestine and suggest that most of the bacteria associated with shrimp intestine are uncultured and novel species.