Kisspeptins are a family of neuropeptides that are essential for fertility. Recent experimental data suggest a putative role of kisspeptin signaling in the direct control of ovarian function. To explore the expression of KISS1 and KISS1 receptor (KISS1R) in human granulosa lutein cells and the potential role of KISS1/KISS1R system in the pathogenesis of polycystic ovary syndrome (PCOS), we measured the concentration of KISS1 in follicular fluid, the expression of KISS1 and KISS1R in granulosa lutein cells, and the circulating hormones. The expression levels of KISS1 and KISS1R were significantly upregulated in human granulosa lutein cells obtained from women with PCOS. The expression levels of KISS1 in human granulosa lutein cells highly correlated with those of KISS1R in non-PCOS patients, but not in patients with PCOS, most likely due to the divergent expression patterns in women with PCOS. Additionally, the expression levels of KISS1 highly correlated with the serum levels of anti-Müllerian hormone (AMH). The expression levels of KISS1 and KISS1R, as well as the follicular fluid levels of KISS1, were not significantly different between the pregnant and nonpregnant patients in both PCOS and non-PCOS groups. In conclusion, the increased expression of KISS1 and KISS1R in human granulosa lutein cells may contribute to the pathogenesis of PCOS. The expression levels of KISS1 highly correlated with the serum levels of AMH. The KISS1 and KISS1R system in the ovary may not have a remarkable role in predicting the in vitro fertilization (IVF) outcome.