Objective：This study aims to investigate the expression pattern of heat shock protein DNAJB8［DnaJ heat shock protein family（HSP40）member B8］ in spermatogenesis. Methods：Quantitative real-time PCR and Western blot were used to determine the transcript levels and protein abundance of DNAJB8 in various mouse tissues，testes at different developmental stages and different germ cell populations. The subcellular localization of DNAJB8 was further assessed by immunofluorescence analysis. Results：DNAJB8 was specifically expressed in the mouse testis. The transcripts of DNAJB8 mRNA increased significantly at postnatal day 21（P21），when round spermatids appeared. However，the protein of DNAJB8 was detected until in P35 mouse testis，where elongating spermatids were highly enriched at this stage. Immunostaining on frozen adult mouse testis and spermatozoa showed that DNAJB8 was observed in late stages of spermatids，and its signal was also present in middle-piece flagellum of spermatozoa. Conclusion：DNAJB8 may function in the elongation of round spermatids during late stages of spermiogenesis.