Abstract: BACKGROUND: Frozen shoulder is a debilitating, long-lasting condition. At Bergen Surgical Hospital we have performed arthroscopic capsular release since 2003 in patients where conservative treatment has failed. The procedure is done as day surgery. The purpose of this study was to evaluate our results. PATIENTS AND METHODS: From June 2003 until October 2005 arthroscopic capsular and ligament release was performed in 66 patients (70 shoulders) with primary frozen shoulder. Oxford shoulder score and range of motion were recorded prospectively. Follow-up was done during autumn 2005 and included subjective evaluation of symptoms, function, satisfaction with the result of the procedure, Oxford shoulder score and clinical examination. RESULTS: 62 out of 66 patients would agree to have the same procedure done again. Degree of satisfaction with the result of the procedure (0 = worst, 10 = best) was 8.6 +/- 1.8 (SD) on average. Ability to work, physical activity and quality of night's sleep improved significantly (p < 0.001). Oxford shoulder score (12 = best, 60 = worst) decreased significantly from 41.0 +/- 7.5 (SD) to 18.4 +/- 7.3 (SD) (p < 0.001). External rotation, abduction and flexion increased significantly (p < 0.001). INTERPRETATION: The results from treatment of frozen shoulder with arthroscopic capsular release are good and suggest that the the condition shoulder is shortened. The procedure may be done safely as day surgery. We feel that more patients may benefit from the procedure.