Abstract Disclosure: M. Paravastu: None. R. Patel: None. Background: Non-Classic Congenital Adrenal Hyperplasia (NCCAH) in women often presents with hirsutism, acne, menstrual dysfunction, or infertility. Subfertility in patients with NCCAH can be attributed to menstrual disorders including oligomenorrhea or secondary amenorrhea. We report a unique case in which a patient with NCCAH with consistently normal menstrual cycles is experiencing infertility. Case Description: A 31 y/o female with no PMH was referred to our Endocrinology Clinic for evaluation of Infertility and elevated 17-Hydroxyprogesterone levels (17OHP). Patient has been having trouble conceiving for the past 2 years, no prior successful pregnancies. She started menstrual cycles at age 17, she reports having regular menstrual cycles. Prior to our evaluation, she was seen in Reproductive Endocrinology who completed hormonal and imaging evaluation. Elevated 17OHP: 286ng/dL. Rest of hormonal workup within normal range. Normal Pelvic Ultrasound. Hormonal workup was repeated in our clinic. 17OHP is elevated at 617.01ng/dL. Rest of lab work returned normal with DHEAS:218.9mcg/dL, TSH: 2.826mcUnits/mL, Free Testosterone: 5.4pg/mL, Prolactin:11.7ng/mL, Beta HCG: negative, LH: 13.5mUnits/mL, FSH: 5.3mUnits/mL, Estradiol 79pg/mL. Cosyntropin stimulation test was completed. Baseline AM 17OHP:469.78ng/dL, Baseline Cortisol: 17.9mcg/dL. 17OHP 30 minutes-post:1216.4ng/dL, Cortisol 30 minutes-post: 18.5mcg/dL. 17OHP 60 min-post: 1051ng/dL, Cortisol 60 minutes post:16.4 mcg/dL. Given Inconclusive Cosyntropin stimulation test results, Genetic Testing was recommended. Genetic testing returned positive for NCCAH, patient’s husband is not a carrier of this gene. She was started on Hydrocortisone therapy for treatment of infertility. Shortly after she started on hydrocortisone therapy, patient did successfully conceive, however the pregnancy later resulted in a miscarriage. Conclusion: Subfertility in patients in NCCAH is thought to be due to menstrual irregularities including oligomenorrhea or secondary amenorrhea. We report the first case of a woman with diagnosis of NCCAH who is experiencing infertility despite having normal menstrual cycles. Presentation: 6/1/2024