In this study the clinical and epidemiological characteristics of congenital adrenal hyperplasia were evaluated retrospectively from the records of 273 patients managed in our clinic over a 25-year period. 21-Hydroxylase deficiency was present in 234 patients (85.7%), simple virilizing form in 134 (110 F, 24 M), salt-losing form in 85 (71 F, 14 M) and late on-set form in 15 girls. 11 beta-Hydroxylase deficiency was diagnosed relatively frequently (13.5%) among our patients with congenital adrenal hyperplasia; one girl had 17 alpha-hydroxylase deficiency and one boy had 3 beta-hydroxy steroid dehydrogenase deficiency. The median chronological age of diagnosis was 12 months (1 day-16.6 years) in patients with classical congenital adrenal hyperplasia. Chromosomal sex was 46, XX in a total of 221 patients and 46, XY in 52. Ninety-one girls were considered to be male before diagnosis was established and male sex was assigned in 31 of them due to development of male gender identity at diagnosis. Parental consanguinity rate among families of patients was higher than the general population in Turkey (56.4% vs 21%). Our overall figures show that the incidence of congenital adrenal hyperplasia is expected to be high due to a high rate of consanguinity in our populations and the patients remain frequently undiagnosed during the neonatal period. Therefore screening may be beneficial in our population.