Twelve water channels (aquaporins) are expressed in mammalian reproductive systems, and play very important roles in maintaining water homeostasis in reproductive cells. Impairment of their functions can result in attenuated male and female fertility. Alteration of AQPs expression is also found in reproductive tissues of the patients with polycystic ovarian syndrome, endometriosis or endometrium carcinoma. A lot of data have increased understanding of the functions and mechanisms of regulation of aquaporins at both the molecular and the clinical level. Researches have also focused on aquaporins as therapeutic targets. This review discusses recent advances in uncovering the physiological and pathophysiological roles of aquaporins in the reproductive systems.