Therapists using mobilization techniques commonly implement a pre- post session (application) evaluation of symptoms. Symptoms usually checked are pain intensity and range of motion. This suggests an immediate effect of the applications. Shoulder impingement syndrome (SIS) is a common cause of shoulder pain and commonly shows restriction in shoulder range of motion, especially shoulder elevation. In this study, the aim was to evaluate the immediate effects of shoulder mobilization on pain and overhead reach in patients with SIS. Methods: 50 patients with SIS were recruited and randomly assigned to mobilization and control groups. Patients in both groups received a single session. In mobilization group, they received transcutaneous electrical nerve stimulation (TENS) and mobilization techniques, while control group received TENS only. Pain intensity and overhead reach distance (ORD) were evaluated pre and post session. Results showed significantly decreased pain intensity and increased ORD in patients of mobilization group. Patients in the control group showed significant decreased pain intensity, however, it was significantly less than the pain reduction achieved in mobilization group. Conclusion:according to the findings, mobilization showed significant immediate effect on pain and ORD in patients with SIS, which supports the practice of pre- post session evaluation used in mobilization.