Abstract Context Serum 17-hydroxyprogesterone (17OHP) and androstenedione (A4) are the conventional biomarkers used to assess disease control in patients with 21-hydroxylase deficiency (21OHD). However, discrepancy between the two is not uncommon, limiting interpretation. Objective To evaluate 11-oxyandrogens in discriminating good versus poor disease control in 21OHD in the setting of discrepant 17OHP and A4. Methods Retrospective analysis of 2738 laboratory assessments obtained as part of Natural History Study of congenital adrenal hyperplasia (CAH) at the National Institutes Health Clinical Center. Patients with discrepant 17OHP and A4 and available sera were selected. A 15-steroid mass-spectrometry panel was performed in sera from patients with 21OHD and age- and sex-matched controls. Patients were categorized in “good” or “poor” control based on clinical assessment (bone age advancement, signs and symptoms of precocious puberty, menstrual irregularity, hirsutism, or hypogonadotrophic hypogonadism). Results Discrepant 17OHP and A4 was found in 469 (17%) laboratory assessments. Of these, 403 (86%) had elevated 17OHP with A4 in reference range. Of 46 patients with available sera, 30 (65%) were in good control. Median fold elevation relative to controls was higher in patients with poor versus good control for 11-hydroxytestosterone (median [interquartile range], 2.82 [1.25-5.43] vs 0.91 [0.49- 2.07], P = .003), and 11-ketotestosterone (3.57 [2.11-7.41] vs 1.76 [1.24-4.00], P = .047). Fold elevation of 11-hydroxytestosterone between 3.48 (sensitivity 97%, specificity 47%) and 3.88 (sensitivity 100%, specificity 40%) provided the best discrimination between poor vs good control. Conclusion 11-Oxyandrogens, especially 11-hydroxytestosterone, may be useful in the management of CAH when conventional biomarkers are inconclusive.