Fifty-six patients with subacromial impingement syndrome (SIS) were randomized to receive either exercise therapy (ET) alone (n=28) or exercise therapy with two doses of Platelet-Rich Plasma (PRP) injections (n=28). The primary outcome was pain reduction, assessed by the Visual Analog Scale (VAS). Secondary outcomes included functionality (Constant-Murley Score, CMS) and QoL (SF-36). Outcomes were assessed at baseline and after 6 months. Overall, the study revealed that both treatments were effective; however, the PRP group demonstrated superior improvements in resting and nighttime pain (VAS scores) and in shoulder abduction strength and range of motion. These findings suggest that combining PRP with ET enhances pain management and specific functional outcomes in SIS.