Anti-Mllerian hormone (AMH) was discovered over 60 years ago for its crucial role in the regression of the Mllerian duct, the female internal genital precursor, during male sexual differentiation. In 1986, the AMH gene was isolated and classified as a homodimeric disulphide-linked glycoprotein, a member of the transforming growth factor β (TGF-β) superfamily of growth factors. It was later established through animal models to have a key role in female folliculogenesis via the regulation of initial and cyclic recruitment of follicles. Over the last decade or so, reproducible data from a diverse number of publications have demonstrated a variety of reasons to measure this hormone in clinical practice. AMH may provide an accurate and highly sensitive means for predicting the onset of female menopause and poor ovarian reserve in those receiving in vitro fertilization (IVF). Furthermore, elevated concentration of AMH is a distinctive feature of polycystic ovary syndrome (PCOS). Not only is it a potential surrogate diagnostic marker of PCOS, but it may also provide prognostic importance that other current diagnostic tools lack. It could also be valuable in the diagnosis and recurrence of granulosa cell tumours since its measurement demonstrates excellent diagnostic sensitivities and specificities. This article briefly discusses the physiological role of AMH in males and females respectively and critically reviews the use of measuring AMH in clinical practice.