PURPOSE: To correlate the plain radiographic findings of a supraspinatus tear with the degree and extent of a supraspinatus tear on MR images. MATERIALS AND METHODS: We retrospectively reviewed the plain radiographs of 35 patients with a supraspinatus tendon tear confirmed by MRI and surgery from July 2004 to June 2006. On the plain radiographs, degenerative changes of acromion and the greater tuberosity and acromiohumeral distance were evaluated. Patients were divided into groups according to the degree and size of the supraspinatus tendon tear and the duration of symptoms. We compared the degenerative changes score and acromiohumeral distance among the groups. RESULTS: There was no statistically significant difference for the degenerative changes score for acromion and greater tuberosity among the groups classified by the degree and size of the supraspinatus tendon tear. However, the acromiohumeral distance was shorter as the extent of the tear was larger; this finding was statistically significant. There was no statistical correlation for the degenerative changes score and the acromiohumeral distance with the duration of symptoms. CONCLUSION: On plain radiographs of the shoulder joint, a decreased acromiohumeral distance is useful to predict the degree and size of a supraspinatus tear, but degenerative changes are not useful to predict the degree and size of a supraspinatus tear and do not correlate with symptom duration.