Serum anti-Mullerian hormone (AMH) levels were measured in 14080 human samples over 6 months using an ELISA method. AMH levels declined with increasing age and varied individually. AMH strongly correlates with antral follicle count and predicts ovarian response to fertility treatments. AMH assessment is valuable for evaluating ovarian reserve, infertility, polycystic ovary syndrome, and menopausal status. While age impacts ovarian reserve, AMH is a better marker as levels decline earlier than other indicators.