Background - A rotator cuff tear (RCT) is a common source of shoulder pain Imaging modalities commonly used for the detection of RCTs include magnetic resonance imaging (MRI) and ultrasound (US).Purpose - to assess the efficacy of US in the diagnosis of rotator cuff tendinopathies and tears, by using ultrasound in comparison to  MRI .Material and Methods - This study was conducted on 30 patients with shoulder pain They underwent ultrasound and MRI of the affected shoulder . Results - MRI was used as a reference test and found that; (53.3%) among the cases had tendinopathy, (36.7%) had a partial thickness tear and (10%) had  a full thickness tear. We used US as an Index test and found that , (50%) among the cases had tendinopathy, (40%) had partial thickness tears and (10%) had full thickness tears. There was a significant relation between the findings of ultrasound and MRI in the diagnosis of rotator cuff tendinopathy and tears. Conclusion  - Ultrasonography is  a cost-effective imaging modality for screening rotator cuff disorders because it is non-invasive,  non- ionizing,  widely available , and has the advantage of dynamic real-time assessment