In this review, the role of anti-Mullerian hormone (AMH) as a regulator and marker of ovarian function is described. Studies in mice showed that AMH is one of the intra-ovarian growth factors regulating primordial follicle recruitment and follicle-stimulating hormone (FSH) sensitivity of growing follicles in an inhibitory manner. Association studies of common variants of the AMH and AMHRII gene suggest that AMH may have a similar role in the human ovary. When it was discovered that serum levels AMH are correlated with the number of growing follicles, AMH gained further clinical interest as a marker for the quantitative aspect of ovarian reserve and as a diagnostic marker for polycystic ovary syndrome (PCOS). (C) 2010 Elsevier Masson SAS. All rights reserved.