Cold-inducible RNA-binding protein(CIRP) is a kind of RNA binding proteins that plays important roles in many physiological processes. The CIRP has been widely studied in mammals and amphibians since it was first cloned from mammals. On the contrary, there are little reports in teleosts. In this study, the Po CIRP gene of the Japanese flounder was cloned and sequenced. The genomic sequence consists of seven exons and six introns. The putative Po CIRP protein of flounder was 198 amino acid residues long containing the RNA recognition motif(RRM). Phylogenetic analysis showed that the flounder Po CIRP is highly conserved with other teleost CIRPs. The 5’ flanking sequence was cloned by genome walking and many transcription factor binding sites were identified. There is a Cp Gs region located in promoter and exon I region and the methylation state is low. Quantitative real-time PCR analysis uncovered that Po CIRP gene was widely expressed in adult tissues with the highest expression level in the ovary. The m RNA of the Po CIRP was maternally deposited and the expression level of the gene was regulated up during the gastrula and neurula stages. In order to gain the information how the protein interacts with m RNA, we performed the modeling of the 3D structure of the flounder Po CIRP. The results showed a cleft existing the surface of the molecular. Taken together, the results indicate that the CIRP is a multifunctional molecular in teleosts and the findings about the structure provide valuable information for understanding the basis of this protein’s function. Cold-inducible RNA-binding protein (CIRP) is a kind of RNA binding proteins that plays important roles in many physiological processes. The CIRP has been widely studied in mammals and amphibians since it was first cloned from mammals. On the contrary, there are In this study, the Po CIRP gene of the Japanese flounder was cloned and sequenced. The genomic sequence consists of seven exons and six introns. The putative Po CIRP protein of flounder was 198 amino acid residues long containing the RNA recognition Phylogenetic analysis showed that the flounder Po CIRP is highly conserved with other teleost CIRPs. The 5 ’flanking sequence was cloned by genome walking and many transcription factor binding sites were identified. There is a Cp Gs region located in promoter and exon I region and the methylation state is low. Quantitative real-time PCR analysis uncovered that Po CIRP gene was widely expressed in adult tissues with the highest expression level i The ovary. The m RNA of the Po CIRP was maternally deposited and the expression level of the gene was regulated up during the gastrula and neurula stages. In order to gain the information how the protein interacts with m RNA, we performed the modeling of the 3D structure of the flounder Po CIRP. The results showed a cleft existing the surface of the molecular. Taken together, the results indicate that the CIRP is a multifunctional molecular in teleosts and the findings about the structure provide valuable information for understanding the basis of this protein’s function.