To report a singleton live birth in a female patient with congenital adrenal hyperplasia (CAH) due to 17-hydroxylase deficiency. Case report. A 29 years old female with CAH due to 17-hydroxylase deficiency presented with infertility. CAH due to 17-hydroxylase deficiency in 46,XX patients is characterized by low serum levels of estradiol (E2) and high levels of progesterone (P). Therefore it is associated with ovulatory dysfunction, ovarian cysts and inadequate endometrial development for embryo implantation. No other infertility factors could be identified. IVF was recommended, considering the complexity of the disorder. Ovulation induction (OI) was achieved with a long GnRH agonist protocol and recombinant FSH (rFSH). All embryos were electively cryopreserved (vitrification) after 5 days of development. Goserelin acetate was administered after menstruation to suppress ovarian synthesis of P. The patient also received 0.5 mg/day of dexamethasone acetate to reduce adrenal synthesis of P. Once P was < 1ng/mL endometrial preparation (EP) with estradiol valerate (6mg/day orally) was initiated. OI was accomplished with 1237,5 IU of rFSH over 11 days. At the end of OI, P was 13 ng/mL and E2< 13pg/mL. Four mature oocytes were retrieved and fertilized (ICSI) by a fresh semen sample. On the fifth day of embryo culture, two morulae were cryopreserved. Goserelin acetate (10,8mg) was administered subcutaneously one month after oocyte retrieval. Three months later, when P< 1ng/mL, EP was started. When endometrial thickness reached 8 mm (18th day of EP), 200mg of micronized progesterone were administered vaginally t.i.d. Five days later, embryos were thawed and transferred into the uterus. β hCG tested positive 10 days later. A singleton pregnancy was confirmed with transvaginal ultrasound at the 6th week of gestational age. Hormonal support (estradiol + progesterone) was maintained until 8 weeks of GA. A live birth occurred at 30 weeks of GA due to fetal distress (true umbilical knot). The neonate was discharged in good conditions after 30 days of neonatal ICU. A live birth was achieved through IVF, cryopreservation of embryos and frozen thawed embryo transfer after the reduction of P synthesis in a patient with 17-hydroxylase deficiency.