Endometriosis is the most common cause of chronic pelvic pain in adolescent girls (50-70%), unresponsive to treatment of oral contraceptives and non-steroidal anti-inflammatory drugs. The most common symptoms of the disease are: acquired or progressive dysmenorrhea, acyclic and cyclic pain, dyspareunia (in sexually active girls), urological symptoms and gastrointestinal complaints. When evaluating an adolescent with suspected endometriosis, a gynecological examination (rectal or vaginal examination) and imaging studies (ultrasonography, magnetic resonance) should be performed. Moreover, in diagnostic process laparoscopy should be carried out in all girls and teenagers with chronic pelvic pain unresponsive to medical treatment. Initial therapy of endometriosis in adolescent girls involves: surgical methods (laparoscopy/laparotomy), hormonal pharmacotherapy (combined contraceptives, progestin-only protocols), GnRH agonists (adolescents over 16 years of age), non-steroidal anti-inflammatory drugs, alternative pain therapies and psychotherapy. Early diagnosis and treatment during adolescence may decrease disease progression and prevent subsequent infertility.