Adipocyte size and number are correlated with fat deposition, which is of major concern to human health and pork producers. To identify quantitative trait loci (QTL) for adipocyte size and number in pigs, a total of 341 F2 animals at 240 days in a White Duroc × Erhualian cross were measured for the area, perimeters, volume and number of adipocyte in abdominal fat. A genome scan was performed on these animals and their parents and grandparents with 183 microsatellite markers spanning the pig genome. Five chromosomal regions showed effects on the traits measured, predominantly on adipocyte size, on pig chromosome (SSC) 1, 4, 7 and 9. Neither of these QTL has been reported before this study. The QTL for adipocyte size detected in this study perfectly correspond to the previously reported QTL for fatness traits on SSC1, 4 and 7. The most significant association was evidenced at 58 cM on SSC7. At the locus, the favorable allele decreasing adipocyte size was unusually originated from the obese Erhualian breed. Only a suggestive QTL was detected for adipocyte number on SSC9. The results shed new lights on the understanding of the genetic basis of fatness traits in pigs.