50 patients with subacromial pain syndrome were randomized to receive either physiotherapy plus a corticosteroid injection (PT+Injection; n=25) or physiotherapy alone (PT; n=25). Outcomes of interest included pain on a Visual Analog Scale (VAS), Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH), Shoulder Pain and Disability Index (SPADI), Western Ontario Rotator Cuff Index (WORC), global rating of change in pain and function, and the incidence of adverse events. VAS pain, DASH, and SPADI scores were significantly better in the PT + injection group at 3 and 6 months follow-up compared to the PT group. Similarly, WORC scores were significantly better in the PT + Injection group at 6 months compared to the PT group. All other outcomes were similar between the two groups. The addition of a corticosteroid injection to PT can provide improvements in pain, function, and disability compared to PT alone for subacromial pain syndrome.