Objective: Congenital adrenal hyperplasia (CAH) is the most common form of primary adrenal insufficiency in children. Neonatalscreening for CAH is effective in detecting the salt-wasting (SW) form and in reducing mortality. In this study, our aim was to estimatethe incidence of CAH in Turkey and to assess the characteristics and efficacy of the adopted newborn CAH screening strategy.Methods: A pilot newborn CAH screening study was carried out under the authority of the Turkish Directorate of Public Health. Newbornbabies of ≥32 gestational weeks and ≥1500 gr birth weight from four cities, born between March 27-September 15, 2017 were includedin the study. Screening protocol included one sample two-tier testing. In the first step, 17α-hydroxyprogesterone (17-OHP) was measuredby fluoroimmunoassay in dried blood spots (DBS) obtained at 3-5 days of life. The cases with positive initial screening were tested bysteroid profiling in DBS using a liquid chromatography-tandem mass spectrometry method to measure 17-OHP, 21-deoxycortisol (21-S),cortisol (F), 11-deoxycortisol and androstenedione as a second-tier test. The babies with a steroid ratio (21-S+17-OHP)/F of ≥0.5 werereferred to pediatric endocrinology clinics for diagnostic assessment.Results: 38,935 infants were tested, 2265 (5.82%) required second-tier testing and 212 (0.54%) were referred for clinical assessment,six of whom were diagnosed with CAH (four males, two females). Four cases were identified as SW 21-hydroxylase deficiency (21-OHD)(two males, two females). One male baby had simple virilizing 21-OHD and one male baby had 11-OHD CAH. The incidence of classical21-OHD in the screened population was 1:7,787.Conclusion: The incidence of CAH due to classical 21-OHD is higher in Turkey compared to previous reports. We, therefore, suggestthat CAH be added to the newborn screening panel in Turkey. The use of steroid profiling as a second-tier test was found to improve theefficacy of the screening and reduce the number of false-positives.