Aims Accurate identification of the successful reduction of a dislocated shoulder could avoid additional episodes of procedural sedation and repeated performance of X-rays. The objective of this study was to assess the diagnostic accuracy of point-of-care-ultrasound (POCUS) in the confirmation of a successful joint reduction in patients with shoulder dislocation. Methods This was a single-centre, prospective observational study set in an urban academic ED in Ireland, with a convenience sample of adult patients with shoulder dislocation on X-ray. Ultrasound was performed on participants before and after joint reduction using a posterior approach technique. The operator's confidence levels were recorded after image acquisition. Results Thirty-three subjects were recruited. All dislocations were correctly identified on pre-reduction US, indicating a sensitivity of 100% (CI 89.42 - 100). Post-reduction US confirmed successful reduction in 30 subjects that were subsequently reported as such on X-Ray, giving it a specificity of 100% (CI 88.43 - 100). Failure to achieve reduction was correctly identified on US in three cases, resulting in post-reduction US Sensitivity of 100% (CI 29.24 - 100) and 100% accuracy (CI 89.42 - 100). Conclusion This study has shown that POCUS, with a posterior approach technique, has 100% sensitivity and specificity in confirming successful shoulder reduction in the ED.