Heritability and genetic and phenotypic correlations were estimated for juvenile growth traits of Pacific abalone Haliotis discus hannai Ino.The estimates were calculated from shell length and shell width measurements on progeny resulting from 12 half-sib families and 36 full-sib families obtained using artificial fertilization of mating three females to each male.The measurements were taken at 10,20 and 30 d after fertilization.It was found that heritability estimates based on sire component ranged from 0.23 to 0.36 for shell length and 0.21 to 0.32 for shell width.Heritability estimates from dam component were larger than those from sire component at three ages,indicating presence of maternal effects,non-additive genetic effects and common environmental effects.Phenotypic correlations were significant at three ages(P < 0.05),with values of 0.92,0.93 and 0.92,respectively.Genetic correlations from the paternal half-sib correlation analysis were highly positive at three ages,with values of 0.50,0.78 and 0.81,respectively.The results suggest that selective breeding is an effective approach to improving growth traits of Pacific abalone stocks. Heritability and genetic and phenotypic correlations were estimated for juvenile growth traits of Pacific abalone Haliotis discus hannai Ino. The estimates were calculated from shell length and shell width measurements on progeny resulting from 12 half-sib families and 36 full-sib families obtained using artificial fertilization of mating three females to each male. The measurements were taken at 10,20 and 30 d after fertilization. It was found that heritability estimates based on sire component ranged from 0.23 to 0.36 for shell length and 0.21 to 0.32 for shell width. Heritability estimates from dam component were larger than those from sire component at three ages, indicating presence of maternal effects, non-additive genetic effects and common environmental effects. Phenotypic correlations were significant at three ages (P <0.05), with values ​​of 0.92, 0.93 and 0.92, respectively. Genetic correlations from the paternal half-sib correlation analysis were highly positive at three ages, with value s of 0.50, 0.78 and 0.81, respectively.The results suggest that selective breeding is an effective approach to improving growth traits of Pacific abalone stocks.