BACKGROUND Sex assignment in infancy for patients with disorder of sex development (DSD) is a challenging problem. Some of the patients with congenital adrenal hyperplasia (CAH) have DSD that may affect their gender identity. OBJECTIVE The study aimed to assess gender identity in patients with CAH. METHODS In this study, 52 patients with CAH, including 22 prepubertal children and 30 adolescents and adults, were assessed using two separate gender identity questionnaires for children and adults based on the criteria of diagnostic and statistical manual of mental disorders, 5th edition. RESULTS In the children group, compatibility was seen between gender identity and rearing gender. In the adult group, there were three cases of mismatching between gender identity and sex assignment composed of two females with poor control and one male with good control with 21-hydroxylase deficiency (21-OHD). Three girls with 11-hydroxylase deficiency (11-OHD) were reared as boy. Two of them with late diagnosis at 5 and 6 years of age had pseudoprecocious puberty. Parents and children did not accept to change the gender. One of them is 36 years old now, is depressed and unsatisfied with her gender, another girl is still child and has male sexual identity. One girl with 11-OHD and early diagnosis at birth with Prader 5 virilization but with good hormonal control was changed to female gender at 12 years of age when female sexual characteristics appeared; she is 34-years-old now, married, and with two children, and she is satisfied with her gender. CONCLUSIONS In patients with CAH, gender identity disorder is a rare finding. Hormonal control, social, familial, and religious beliefs have impacts on gender identity of these patients.