Retinoid receptors are ubiquitous throughout the animal kingdom both in invertebrates and vertebrates, including the humans. In vertebrates, the retinoid X receptor (RXR) is suggested to be responsible for a variety of functions including growth and reproduction. However, reports are very scarce on the exact function of the RXR in crustaceans. In the present paper, we report the sequence information on the DNA binding domain (DBD) of the retinoid hormone receptor gene (RXR) of a field crab, Paratelphusa sp. from the Indian peninsula. BLAST analysis of the RXR-DBD shows considerable sequence homology with other brachyuran crabs, such as, Uca pugilator, Gecarcinus lateralis and Carcinus maenas. Taking cues from the GenBank database, we could also draw out the identity of this domain of the RXR with major phylogenic groups, including insects, molluscs and vertebrates. The sequence analysis of the RXR-DBD of the crab revealed remarkable sequence similarity to crustaceans and vertebrates, as compared with those of the insects.