The cDNA encoding porcine RACK1 protein was isolated from porcine spleen cDNA library. The deduced protein sequence of porcine RACK1 cDNA shows that it contains 317 amino acid residues, and shares nearly 100% identity with its vertebrate counterparts. Noticeably, the RACK1 protein was differentially expressed in various porcine tissues. High expression of RACK1 protein was observed in the tissues including thymus, pituitary, spleen and liver, whereas there was no detectable expression in muscle. The genomic DNA of porcine RACK1 with approximate 7.5 kb was constructed by both polymerase chain reaction amplification and genomic library screening. It consists of eight exons intervened by seven introns, and most of the intron/exon splice sites conform to the GT/AG rule. The promoter region contains functional serum response element, YY1-like binding site and AP1 site, which is supported by the finding that the expression of RACK1 gene in cultured porcine ST cells has a serum response as well as a TPA response.