Among several parameters involved in the age-dependent reduction in conception rate, intra-ovarian factors, specially the follicular oocyte complex, play a major role. The aim of endocrine challenge tests is to assess ovarian follicular reserve. Basal serum FSH determination on day 3 of the cycle is easily measurable, inexpensive. Its sensitivity is increased with a clomiphene citrate challenge test. Both GnRH agonist stimulation test and exogenous FSH test allow to evaluate more directly the ovarian function. However they are more invasive, expensive and need further standardisation.