Objective: Because congenital adrenal hyperplasia (CAH) and autism spectrum disorders (ASD) is rarely seen, it is difficult to assess whether the increased incidence of ASD in girls with CAH. ASD behaviors and 2D: 4D finger ratio changes in patients with androgen overproduction have been reported. The aim of this study is determining the 2D:4D finger ratios and ASD features in girls with CAH and normal control group. Methods: The study group will consist of thirty female children and adolescents between the ages of 3 and 15 who are diagnosed with classic CAH who were followed at the Pediatric Endocrinology Department of Duzce University Medical Faculty Hospital. For the control group, 30 healthy children and adolescents equalized with CAH patients in terms of age and gender will be taken. Al patients and controls examined for psychiatric disorders. by clinicians Patients and control groups filled Autism Behavior Checklist and semistructured sociodemographic form that evaluated the gender, age, pregnancy and birth complications, history of mothers cigarette and alcohol use. 2D:4D ratios were measured in both of control and CAH groups. Findings: KAH group right and left hand 2D:4D ratios were statistically lower compared to controls and also lower 2D:4D ratios had association with high ABC scores. When compared with control group, CAH group ABC scores were significantly higher. In KAH group there was a positive correlation between 2D:4D ratios and ABC scores. Conclusion: In light of present study findings, suggest that high androgen may have effect on low 2D:4D ratios and high ASD symptoms. Further researches with a large sample are needed in this field. [Anadolu Psikiyatri Derg 2017; 18(4.000): 395-403]