Prostaglandins have important roles in the male reproductive system. In this study, we report on the distribution and regulation of cPGES during postnatal development of mouse testis. The expression of cPGES was weak in testis 5 days after birth and increased through the 10th and 15th day. From the 20th day onward, the cPGES expression in testis reached the level of adult mice. cPGES was expressed at a constantly low level in Sertoli cells in the testis from infant to adult stages. With the occurrence of meiosis during puberty, a high level of cPGES was detected in the spermatocytes and round spermatids, which was then maintained throughout the adulthood. In addition, cPGES was found highly expressed in the epididymis, seminal vesicles and vas deferens This suggests that cPGES in Sertoli cells in infant to juvenile mouse testis contributes to a basic PGE2 synthesis in seminiferous tubules. However, the high level of cPGES in spermatocytes and spermatids may maintain a high amount of PGE2 in seminiferous tubules, which may be tightly coupled with the spermatogenic cycle.