Arthroscopic and open shoulder surgery have to be combined for a successful surgical therapy of the shoulder joint. A surgeon performing open surgery only or just treating by arthroscopic measurements can not cover the full spectrum of modern shoulder surgery. Isolated diagnostic arthroscopy is rarely indicated. Far more common, diagnostic arthroscopy is combined with an operative procedure both to confirm preoperative assessment of pathology and to uncover associated lesions. The results of arthroscopic stabilisation of chronic anterior posttraumatic dislocations fail to compare with high success rates of open procedures. Better patient selection will probably be the key to improving results. In case of acute traumatic first time dislocation in young highly sportive athletes the arthroscopic repair of the isolated Bankart-Perthes lesion offers the attractive advantage of anatomic reconstruction with minimal soft tissue dissection. Further indications for arthroscopic measurements of pathologies of the glenohumeral joint are synovectomy in rheumatoid arthritis, capsulotomy of shrunk capsule in frozen shoulder and tenodesis for lesions of the long head of the biceps. The arthroscopic subacromial decompression according to Ellman is the most often and successful performed procedure at the shoulder joint and has overcome the classic Neer open acromioplasty. For smaller tears of the supraspinatus tendon the arthroscopic acromioplasty can be combined with an all arthroscopic suture repair or with an mini-open repair. Larger tears of the rotator cuff are still the domain for open reconstructive procedures. In case of associated or isolated AC-joint arthritis an arthroscopic Mumford procedure can be performed. For chronic calcific tendinitis isolated arthroscopic excision of the calcium deposit is of great value. Additionally, acromioplasty is needed for true mechanical obstruction of the subacromial space.