Rotator cuff lesions are frequently associated with varying degrees of disability. Recently, arthroscopic techniques have been established that provide visualization of the glenohumeral joint and subacromial bursa and allow a thorough evaluation of rotator cuff lesions and associated pathology.Arthroscopic procedures for evaluating and treating rotator cuff lesions are described. A system for classifying rotator cuff lesions, based on arthroscopic findings, is presented. The classification of these lesions provides an accurate description of the involved pathology and may aid in predicting the response to various forms of treatment.Shoulder arthroscopic techniques are gaining popularity and early clinical results are encouraging. Although open surgical procedures about the shoulder have withstood the test of time, often providing satisfactory results, we believe that shoulder arthroscopy plays a major role in the evaluation and treatment of rotator cuff lesions.