Ten patients with clinically suspected rotator cuff impingement syndrome were evaluated with magnetic resonance (MR) imaging, double contrast arthrography, and conventional radiography. An area of increased signal intensity in the tendinous portion of the rotator cuff was seen in eight of ten patients on images obtained with a short repetition time (TR) and short echo time (TE) and those obtained with a long TR and long TE with spin-echo sequences. Microscopic findings, available in five patients, indicated that these areas of increased intensity corresponded to degeneration and inflammation of the rotator cuff. A previously injected long-acting steroid preparation combined with a local anesthetic, which also produces an area of increased signal intensity on long TR, long TE images, can cause problems with image interpretation. No tears of the rotator cuff were detected with MR imaging. However, a full-thickness cuff tear was detected with arthrography in three patients. Although based on a relatively small group of patients, these preliminary findings suggest that MR imaging is capable of demonstrating rotator cuff abnormalities in patients with impingement syndrome.