The sex-determining system of yellowtail (Japanese amberjack), Seriola quinqueradiata, is not known. In this study, we identified the sex-linked locus in yellowtail and we characterized the sex-determining system by genetic linkage analysis conducted on 19 female and 19 male progenies from a single family. The associations between phenotypic sex and genotypic data of 71 microsatellite markers selected from yellowtail genetic linkage map were tested. The putative sex-determining locus is located between locus Sequ21 and locus Sequ17 in LG12, and the sex-linked alleles were inherited from the female parent. This result suggests that yellowtail has a ZZ-ZW sex-determining system, and that it would be possible to use these sex-linked markers to discriminate the sexes. © 2010 Elsevier B.V.