In conclusion, we provide the fist report on the isolation and thorough characterization of denitrifying bacteria from shrimp culture pond sediments. The genotypic characteristics of some of the denitrifying isolates recovered in the present study show that there exist a diverse group of heterotrophic bacteria with genes yet to be characterized,that are involved in denitrification. Moreover studies on the diversity and physiology of denitrifying bacteria may lead to identification of denitrifying bacteria inshrimp culture pond sediments. Our results demonstrate the ability of the marinobacter isolates to carry out denitrification under ozxic,oxygen tolerant and anoxic conditions. Most of the denitrifying isolates harbored nirS gene and belonged to the order alteromonadales. The study has showed that simple experiments can be used to check denitrification properties along with RT-PCR to confirm nirs gene expression. Though the observersity in this study might be an underestimate of the existing denitrifier communities, large scale analysis of such ecosystems would help resolve the same. Without characterizing the distribution and abundance of these isolates, their role in ecosystem functioning remains unknown and hence future research through application of culture-independent molecular techniques will focus on finding their in situ importance and whether they really represent the denitrifying members in shrimp culture ponds.