Objectives: To determine the frequency and severity of endometriosis in adolescent and teenager girls with chronic pelvic pain (CPP) who fail to respond to medical treatment and to evaluate the outcome of radical laparoscopic surgery for severe endometriosis. Design: Retrospective review of case records of all girls under the age of 21 years who underwent diagnostic and/or operative laparoscopy for CPP unresponsive to medical treatment between January 2001 and December 2003. The operative findings and the response to surgery were retrospectively reviewed. Results: Thirty-one girls were referred. No pelvic abnormalities were detected in 11 patients (35.5% ). Endometriosis was detected in 11 (35.5% ). Six had severe endometriosis. Other diagnoses included: non-functional non-endometrioticovarian cyst (4 patients), functional ovarian cyst (1 patient), hydrosalpinx (bilateral, 1 patient; unilateral, 1 patient) and obstructed uterine horn (2 patients). Of those with severe disease all six were treated laparoscopically without complications. Five were rendered pain free and one had an improvement in symptoms. Conclusions: Endometriosis can occur in adolescent and teenager girls. Laparoscopy should be carried out in all adolescents and teenagers with CPP unresponsive tomedical treatment. This the first study reporting the outcome of radical excision treatment for severe endometriosis in this age group and early results are encouraging. Objectives: To determine the frequency and severity of endometriosis in adolescent and teenager girls with chronic pelvic pain (CPP) who fail to respond to medical treatment and to evaluate the outcome of radical laparoscopic surgery for severe endometriosis. Design: Retrospective review of case records of all girls under the age of 21 years who underwent diagnostic and / or operative laparoscopy for CPP unresponsive to medical treatment between January 2001 and December 2003. The operative findings and the response to surgery were retrospectively reviewed. Results: Thirty-one girls were referred. Six had severe endometriosis. Other diagnoses included: non-functional non-endometrioticovarian cyst (4 patients), functional ovarian cyst (1 patient (35.5%) ), hydrosalpinx (bilateral, 1 patient; unilateral, 1 patient) and obstructed uterine horn (2 patients). Of those with severe disease all six w Five of rendered pain free and one had an improvement in symptoms. Conclusions: Endometriosis can occur in adolescent and teenager girls. Laparoscopy should be carried out in all adolescents and teenagers with CPP unresponsive to treatment. This the first study reporting the outcome of radical excision treatment for severe endometriosis in this age group and early results are encouraging.