The heritable components of many traits in which livestock producers strive for improvement comprise a number of genetic loci. Many workers have now reported the identification of such quantitative trait loci (QTL) using model crosses between divergent breeds or lines in combination with whole genome scans using mapped DNA markers. Such methods rely on two or three generation pedigrees in order to be able to trace the inheritance of markers and the QTL. However, it is not yet clear if such QTL have application in commercial pig populations. The AFLP™ technology is a very efficient method for identifying markers segregating in any population. We have previously reported the successful use of the AFLP™technology and bulk segregant analysis (BSA) for the detection of markers associated with pig coat colour, a monogenic trait (Plastow et al 1998). We set out to determine whether these methods could be used for the detection of loci associated with quantitative traits directly in commercial populations.