Objective:To investigate expression and distribution of calreticulin (CRT) in the adult mouse testis and explore the preliminary function of CRT during testes development and spermatogenesis. Methods:The expression and distribution of calreticulin (CRT) in the adult mouse testis were detected by western blotting (WB) and Immunohistochemistry (IHC). Results:Western blotting result showed CRT expressed highly in mouse testis. Immunohistochemistry result revealed positive signals were widely distributed while strong signals were mainly in primary spermatogonia and Leydig cells. Conclusion:CRT expressed highly in adult mouse testis,and it may be involved in spermatogonia self-renew/differentiation and testosterone secretion mechanisms.