Females from different wild-type laboratory populations of Drosophila melanogaster differ genotypically in their degree of mating discrimination against mutant yellow males. The chromosomal organization of this difference was examined in two wild-type laboratory strains by experimental observation of the mating propensities of hybrid females in a mass-mating, multiple choice situation. The results indicate that the strain difference is polygenic in origin, involving loci on both the X-chromosome and autosomes. Reciprocal crosses revealed no maternal/cytoplasmic effects. The mating scores of parental, F1 and backcross females fit well to a model of additive chromosomal effects, with X-linked loci being recessive, and autosomal loci overdominant, for increased mating with yellow males. However, interactions, arising most probably from recombination, led to increased mating with yellow on the part of F2 females. In addition to the difference in female discrimination against yellow males, male/female interaction was found for the mating speed of flies from the two strains. These results are discussed in the light of previous studies of mating preferences in D. melanogaster. It is suggested that genetic variation in female mating preferences may be an important source of variation in the reported mating success of mutant yellow males.