The X chromosome is highly conserved in both gene content and size across most euthenan mammals. Most whole genome maps either exclude or have very little data on the chromosome. Radiation hybrid (RH) mapping allows for the creation of a high resolution map using both polymorphic and non-polymorphic markers. The INRA Minnesota porcine Radiation Hybrid (IMpRH) panel was used to create a high resolution comparative map of the porcine X chromosome. This map is composed of 145 BAC end sequences (BESs) with an average spacing of 1.07Mb and has comparative coverage of 91% of the human X chromosome. The map is broken into three linkage groups due to the presence of the centromere and high retention around the hypoxanthine phosphoribosyl transferase (HPRT) gene. This maps shows very high conservation of the X chromosome between the pig and human. To compare this map to previous porcine X chromosome maps, microsatellite and gene markers were incorporated into the map. Both microsatellite and gene marker positions differed slightly from previous maps. Most of the differences were probably due to large gaps between markers in the previous maps. Compared to previous maps, this map is composed of the largest number of markers, arranges the chromosome into the smallest number of linkage groups, and is the highest resolution map reported to date.