A 45-year-old man presented with severe left shoulder pain that was not associated with trauma. Plain radiography with the arm in an elevated position and ultrasonography demonstrated calcium deposits at the anterior acromial insertion site of left deltoid muscle. Conservative management could successfully relieve pain. At the 3-year follow-up, the calcification completely disappeared. To the best of our knowledge, calcium deposits at the acromial insertion site of the deltoid have not been reported in the literature. Clinicians who suspect calcific tendinitis but do not observe calcification around the rotator cuff should carefully palpate and examine other sites, such as the deltoid origin, and use ultrasonography or radiography.