One of the major determining factors in the price of market hogs today isbackfat depth. Therefore, identification of regions of the genome affecting thistrait is necessary. Gene-mapping technologies have provided scientists thenecessary reagents to conduct genomewide searches for genes affecting anyphenotype determined in part by the genetic makeup of the animal. Over the pastfew years, several experimental crosses have been used to detect quantitativetriat loci (QTL) for fatness and meat quality traits in pigs. In an intercrossbetween Large White and Meishan pigs, 81 F2 progenies in 1998 were slaughteredand phenotyped for fat deposite traits. F2 animals, their parents, and theirgrandparents were typed for molecular markers covering chromosomes (SSC)1,2,3,4,6 and 7, since previous studies had revealed QTL affecting fatnesstraits on these chromosomes. Linear model and least square analyses were usedfor mapping these traits. Furthermore, a QTL accounting for imprinting effectswas used. A total of 14 QTL at chromosome-wide level were detected on SSC1, 3-4,6 and 7 for 12 fatness traits. There were evidences for imprinting effects onSSC7 for four traits at 60 cM and nearby. There were QTL for average backfatthickness (BFT) on SSC1, 4 and 7. Among them, BFT QTL on SSC1 and 7 may be thecommon locus for Sus scrofa. QTL for internal fat percentage was on SSC7 and QTLfor average sidefat on SSC6.