Polymorphism of microsatellites S0083 and S0090 as well as of the second exon and second intron of the pGH (porcine growth hormone) gene was determined for 293 pedigrees obtained from crossing of 12 F1 (Zlotnicka Spotted x Polish Large White) boars with 64 F1 (Zlotnicka Spotted x Polish Large White) sows, experimental material arranged for a QTL mapping project. Microsatellites were genotyped by capillary electrophoresis of PCR products in an ABI PRISM 310 Genetic Analyser PERKIN-ELMER. The PCR-RFLP polymorphism of the GH gene was identified using HaeII and MspI restriction endonucleases. The following order of linked loci was established: GH-S0083-S0090. This is important information for the mapping of QTLs on chromosome 12.