Background: While the overall diagnostic sensitivity of the physical exam is reportedly as high as 90%, imaging studies are often performed to confirm the diagnosis of shoulder impingement syndrome and rule out other pathologies. If the decision to obtain radiographs is made, they should be obtained bilaterally, rather than only on the affected side, to evaluate potential anatomic differences and to rule out other pathologies such as calcific tendinitis or arthritic changes. Ultrasonography is particularly useful in assessing the rotator cuff, the subacromial bursa and the long biceps tendon. Ultrasonographic examination must comprehensively cover all shoulder structures that may participate in subacromial disease. In the initial phase of shoulder impingement, swelling compared to the contralateral side may be noted. MRI is the best imaging test prior to arthroscopic surgery. Advantages include the following: Noninvasive, No radiation, Able to detect intrasubstance tendon degeneration or partial rotator cuff tears, Able to detect inflammation, edema, hemorrhage, or scarring, Able to be used with an intra-articular contrast agent (eg, gadolinium), improving the MRI ability to detect partial rotator cuff tears. Disadvantages include the following: Not able to accommodate patients with claustrophobia. Not able to accommodate patients with pacemakers or other metal implants or particles. Dependent on quality of the MRI machine. Dependent on skill of technician performing the imaging and the radiologist interpreting the images and Expensive. Keywords: Magnetic Resonance Imaging, Ultrasound, shoulder impingement syn