Lesions of the subscapularis tendon are often underdiagnosed in clinical practice. Relevant ruptures, however, lead to a decentering of the humeral head followed by pain and loss of function. Specific clinical tests and the modern methods of imaging allow for the correct diagnosis and preoperative classification. Arthroscopy permits the precise structural diagnosis of subscapularis tendon lesions. Retracted lesions require an intraarticular as well as extraarticular visualization of the tendon and the surrounding structures. The arthroscopic reconstruction of the subscapularis tendon requires not only are a profound understanding of shoulder anatomy and advanced technical skills, but the fixation technique with sufficient release of the tendon is also needed. There is still only little data in the literature on the outcome after arthroscopic reconstruction. However, using the appropriate technique and respecting the limits of indication, good results can be attained.