Adrenarche is characterized by the increase in adrenal androgen production, namely dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) that occurs around 6 years of age. These steroids are secreted by the zona reticularis (ZR) of the adrenal gland. This is associated with pubarche or the increase in androgen-dependent hair growth at the time of puberty. The increase in adrenal androgen production can be explained by the increase in the expression of DHEA-synthesizing steroidogenic enzymes in the ZR. Adrenarche is an event independent of gonadarche and is found only in humans and select nonhuman primates. Although numerous prenatal and postnatal factors are important in the onset of adrenarche, a specific adrenal cortical androgen-stimulating hormone has not been identified. Evidence also exists for a role for adrenarche in behavior, skeletal maturation, and postpubertal well-being. Adrenarche is influenced by sex and race, and some of this variation may be related to the insulin and insulin-like growth factor (IGF) signaling pathways. In addition, children with premature and exaggerated adrenarche may be predisposed to certain diseases later in life.