Background: Hip arthroscopy has become an established procedure in adults with well-published results. These techniques have been extended to the teenage population, but the literature remains limited in regard to indications, efficacy, outcomes and complications specific to the paediatric population. Hypothesis/purpose: The purpose of this study was to report the short-term outcome of the arthroscopic treatment of cam-type femoroacetabular impingement (FAI) in the skeletally immature adolescent population with open growth plates, with the hypothesis that it is a safe procedure, with good clinical outcomes and low complication rates. Study design: The study design of this article was a multicentre prospective longitudinal case series. Methods: From 2008-2009, 34 consecutive patients who were 18 years or younger at the date of operation (41 hips) with open proximal femoral growth plates had arthroscopic hip surgery for treatment of cam-type FAI and associated lesions by use of the lateral decubitus position by two surgeons. Data were collected prospectively including the modified Harris hip score (MHHS), nonarthritic hip score (NAHS), satisfaction survey and complications. Mean follow-up was 14 months (range 1-2 years). Results: All hips were available for review. The mean age of patients was 15.7 years with the most common sport activity being Australian Football League, netball and rugby. All patients had cam-type impingement, with the most common associated lesions being acetabular rim lesions (82.9 ) and pincer impingement (22 ). The labrum underwent debridement in 31.7 of cases, and was repaired in 17.1 . The MHHS and NAHS improved in all patients post-operatively, 77.39-94.15 and 76.34-93.18, respectively. A percentage of 78.1 were able to return to full sporting activity and 88.2 were satisfied with the operation. There were no complications. Conclusions: Using hip arthroscopy to treat cam-type impingement and associated lesions in the adolescent population, we confirmed our hypothesis with observed high satisfaction levels, return to sports, significant improvement in post-operative hip scores (MHHS and NAHS) and no complications.