The cDNAs for Machado-Joseph disease protein 1 homolog (MJD1), cell division control protein 42 homolog precursor(CDC42) and necdin (NECD) genes of pig were amplified using the reverse transcriptase polymerase chain reaction (RT-PCR) based on the conserved coding sequence information of the MJD1, CDC42, and NECD genes from mouse and other mammals and the referenced porcine EST sequence information. Tissue expression analysis showed the swine MJD1, CDC42, and NECD genes were obviously differentially expressed in different tissues including muscle, heart, liver, backfat, kidney, lung, small intestine, and large intestine. Our experiment established the primary foundation for further research on these three swine genes.