In females, absence of at least three consecutive menstrual cycles when otherwise expected to occur or cessation of pubescence (primary and secondary amenorrhea) are the symptoms of anorexia nervosa, secondary to hypogonadotropic hypogonadism. Disturbances in sexual organs are seen in inappropriate for age pelvic ultrasound scanning. The aim of the study was to determine the ovarian and uterine maturity at the onset of anorexia nervosa (AN) in adolescence, using pelvic ultrasound scanning, and their relations to clinical factors describing the course of AN. Material and method: The group consisted of 38 adolescent girls with anorexia nervosa diagnosed acc. to ICD-10 criteria – mean age 14.3±2.1 years, mean age at the beginning of AN symptoms 13±2.3 years, mean BMI 14±1.6 kg/m2. On initial assessment, all girls underwent physical examination, clinical interview concerning AN symptoms and pelvic ultrasound scanning. Results: Sixteen patients (42%) had primary amenorrhea. In 32% of patients cessation of menses occurred before a significant decrease in weight. Ovarian and uterine volumes significantly below the expected were found in 11 and 15 patients with secondary amenorrhea, respectively. The varian and uterine maturity was related to shorter duration of amenorrhea and longer duration of adequate menstruation before the onset of AN. There were no BMI differences between the groups with more and less mature ultrasound picture.