Fifty-five microsatellite markers were scored in an F2 population of pigs (n =114 females) developed at the University of Nebraska. The population wasproduced by crossing a line previously selected for 10 generations using anindex of ovulation rate and embryonal survival and a line selected at random.The lines were from a common base population and differed by 6.7 ovulations and3.1 fetuses at 50 d of gestation. Ovulation rate and number of fully formed andmummified pigs were recorded for each female. Data were analyzed with regressionmodels that included random animal effects. Likelihood-ratio tests were used totest for quantitative trait loci (QTL) effects by deviating the log-likelihoodfor the full model that included additive and dominance QTL effects from thelog-likelihood for the reduced model that did not contain QTL effects. A QTL forovulation rate was found on chromosome 8 (P < .001) with an additive effect of3.07 ovulations. Other evidence of potential QTL affecting ovulation rate wasfound on chromosomes 4 (P < .10), 13, and 15 (P < .05). Effects on chromosomes4, 13 and 15 were not significant for fan experiment-wise threshold value of P <.001. No significant QTL for litter size or number of mummified pigs were found.Additional data are needed to confirm the location and the effect of QTL foundfor ovulation rate before markers associated with them can be used inmarker-assisted selection.