Background: Subacromial impingement syndrome (SAIS) is one of the most frequently entities involved in the shoulder complex characterized by pain and functional restrictions. This condition is caused by the impingement of the tendons of the rotator cuff, particularly the supraspinatus tendon, head of the biceps brachii, and subacromial bursa between the head of the humerus and coracoacromial arch. The main goals of SAIS treatment are to control pain and increase the range of motion (ROM) in order to enable healing of the compromised rotator cuff. Many programs including electrotherapy, manual therapy, passive, active and active assistive ROM exercises, and stretching and strengthening exercises to the rotator cuff and thoracoscapular muscles are frequently used for the conservative treatment of this complex process. The aim of this comparative study is to investigate the most efficient method for improving pain and quality of life and increasing shoulder range of motion in patients with Subacromial Impingement Syndrome.