Study design: A cross-sectional inter-examiner agreement and reliability study among physical therapists in primary care. Background: musculoskeletal ultrasound (MSU) is frequently used by physical therapists to improve specific diagnosis in patients with shoulder pain, especially for the diagnosis rotator cuff tendinopathy (RCT) including tears. Objectives: To estimate the inter-examiner agreement and reliability in physical therapists using MSU for patients with shoulder pain. Methods: Physical therapists performed diagnostic MSU in 62 patients with shoulder pain. Both physical therapists were blinded to each other's results and patients were not informed about the test results. We calculated the overall inter-examiner agreement, specific positive and negative inter-examiner agreement, and inter-examiner reliability (Cohen's Kappa's). Results: Overall agreement for detecting RC ruptures ranged from 61.7% to 85.5% and from 43.9% to 91.4% for specific positive agreement. The specific negative agreement was lower with values ranging from 44.4% to 79.1% for RC ruptures. Overall agreement for other pathology than ruptures related to SAPS, ranged from 72.6% to 93.6% and from 77.3% to 96% for specific positive agreement. The specific negative agreement was lower with values ranging from 44.4% to 79.1% for RC ruptures and 52.5%–83.3% for other pathology than ruptures related to SAPS. Reliability values varied from substantial for any thickness ruptures to moderate for partial thickness ruptures and fair for full thickness tears. Moreover, reliability was fair for cuff tendinopathy. The reliability for AC arthritis and no pathology found was fair and moderate. There was substantial agreement for the calcifying tendinopathy. Conclusions: Physical therapists using MSU agree on the diagnosis of cuff tendinopathy and on the presence of RCT in primary care, but agree less on the absence of pathology.