Objective Extracellular signal-regulated kinase (ERK), c-jun Nterminal kinase (JNK), and p38 MAPK are three major members of mitogenactivated protein kinases (MAPKs) subfamilies. Clarifying the localization of the three activated MAPKs in testes will help us to understand their functions in spermatogenesis. Methods The expression of phospho (p-) ERK, p-JNK , p-p38 MAPK was detected in normal adult rat testes by the immunohistochemical method. Results p-ERK , one of the MAPKs, expressed prominently in the nuclei of spermatogonia, spermatocytes (preleptotene to pachytene spermatocytes), and elongating spermatids（step 9-12）. While, p-JNK was localized at sites of intraepithelial contact between the SertoliSertoli cells and Sertoligerm cells (especially step 19 spermatids). Meanwhile, the distribution of p-p38 MAPK, the third member of MAPKs, was a little different. Besides its localization in the seminiferous epithelium, the strongest staining of p-p38 MAPK was presented in the cytoplasm of Leydig cells. Conclusion The three members of MAPKs are distributed differently in normal rat testes, which strongly suggests that they regulate the different processes in spermatogenesis. ERK may be involved in controlling germ cell mitosis, meiosis and spermiogenesis, and JNK may modulate actin dynamics to regulate the migration of spermatocytes and spermatids in seminiferous epithelium. Except being combined with JNK to control the spermiati