NCOR1 (nuclear receptor co-repressor1) encodes a protein that represses the expression of the targeted genes by promoting chromatin condensation and disabling access to the transcription machinery. So far, only a few NCOR1 EST sequences are available, and the chromosomal location of NCOR1 is unknown in the porcine genome. In this study, we have localized NCOR1 to the end of pig chromosome (SSC) 12 by a porcine radiation hybrid panel. The expression profile of NCOR1 was clarified using RNA from 18 tissues, and it is expressed ubiquitously in pigs. We did not identify any missense mutation in the exonic region encoding the first SANT domain of the NCOR1 protein, although we found six SNPs and two deletions in intron 12, and three SNPs and one deletion in intron 13, using DNA of 10 founder animals in a White Duroc x Erhualian intercross. These polymorphic markers can be integrated into a genome scan for identifying the QTL affecting economically important traits in pigs.