Context: Anti-Mullerian hormone (AMH), which is secreted by immature Sertoli cells, triggers the involution of the fetal Mullerian ducts. AMH is a testis-specific marker used for diagnosis in infants with ambiguous genitalia or bilateral cryptorchidism. Aim: The aim of the study was to describe the ontogeny of AMH secretion through life in healthy males. Setting:This was a population-based study of healthy volunteers. Participants: Participants included 1027 healthy males from birth (cord blood) to 69 yr. A subgroup was followed up longitudinally through the infantile minipuberty [(in cord blood, and at 3 and 12 months), n = 55] and another group through puberty [(biannual measurements), n = 83]. Main Outcome Measures: Serum AMH was determined by a sensitive immunoassay. Serum testosterone, LH, and FSH were measured, and pubertal staging was performed in boys aged 6 to 20 yr (n = 616). Results: Serum AMH was above the detection limit in all samples with a marked variation according to age and pubertal status. The median AMH level in cord blood was 148 pmol/liter and increased significantly to the highest observed levels at 3 months (P <0.0001). AMH declined at 12 months (P <0.0001) and remained at a relatively stable level throughout childhood until puberty, when AMH declined progressively with adults exhibiting 3-4% of infant levels. Conclusion: Based on this extensive data set, we found detectable AMH serum levels at all ages, with the highest measured levels during infancy. At the time of puberty, AMH concentrations declined and remained relatively stable throughout adulthood. The potential physiological role of AMH and clinical applicability of AMH measurements remain to be determined