One of the largest detriments in the abalone aquaculture industry is the inherently low growth rate of this marine gastropod. In order to confront this issue, greater molecular knowledge is needed on growth traits. Therefore, transcriptome analyses were performed using RNA-Seq for groups of California red abalones (Haliotis rufescens) cultured under the same conditions, but with high growth rates (HGR) or low growth rates (LGR). De novo assembly generated 44312 contigs used as references for RNA-Seq analysis. Results showed a total of 1437 differentially expressed contigs, among which, 435 were up-regulated in the HGR group and 1002 in LGR individuals. Overall, LGR abalones evidenced a greater number of exclusive transcripts and differentially transcribed genes. These results provide a valuable resource of novel transcripts in this species and further understandings of the molecular bases regulating growth traits in Haliotis rufescens.