A multigeneration crossbred Meishan-White composite resource population was usedto identify quantitative trait loci (QTL) for age at first estrus (AP) and thecomponents of litter size: ovulation rate (OR; number of ova released in anestrous period) and uterine capacity (UC). The population was established byreciprocally mating Meishan (ME) and White composite (WC) pigs. Resultant F1females were mated to either ME or WC boars to produce backcross progeny (BC) ofeither 3/4 WC 1/4 ME or 1/4 WC 3/4 ME. To produce the next generation (F3), 3/4WC 1/4 ME animals were mated to 1/4 WC 3/4 ME animals yielding half-blood (1/2WC 1/2 ME) progeny. A final generation (F4) was produced by inter se mating F3animals. Measurements for AP and OR were recorded on 101 BC, 389 F3, and 110 F4gilts, and UC data were from 101 BC and 110 F4 first parity litters. A genomicscan was conducted with markers (n = 157) spaced approximately 20 cM apart. Allparental, F1, BC, and F4 animals but only 84 F3 animals were genotyped andincluded in this study. The QTL analysis fitted a QTL at 1-cM intervalsthroughout the genome, and QTL effects were tested using approximate genome-widesignificance levels. For OR, a significant (E[false positive] < .05) QTL wasdetected on chromosome 8, suggestive (E[false positive] < 1.0) QTL were detectedon chromosomes 3 and 10, and two additional regions were detected that maypossess a QTL (E[false positive] < 2.0) on chromosomes 9 and 15. Two regionspossessed suggestive evidence for QTL affecting AP on chromosomes 1 and 10, andone suggestive region on chromosome 8 was identified for UC. Further analyses ofother populations of swine are necessary to determine the extent of allelicvariation at the identified QTL.