Partial-thickness tearing of the rotator cuff is common; however, relatively little is written on the subject. We reviewed 39 patients with partial-thickness rotator cuff tears who underwent acromioplasty, debridement of the abnormal tissue, and tendon suturing. Follow-up averaged 55 months (range 13 to 132 months). Twenty-three (59%) patients had an excellent result, 10 (26%) patients had a satisfactory result, and 6 (15%) patients had an unsatisfactory result. Four of the six patients with unsatisfactory results had also had unsuccessful previous surgery. Thirty-five (90%) patients rated their response to surgery as either much improved or improved. No complications occurred, and to date no reoperations have been required. Diagnosis of partial-thickness rotator cuff tears can be challenging. Magnetic resonance imaging supplies the most complete information about tendon structure. Conservative treatment is reasonable for most partial-thickness tears. When surgical treatment is indicated, acromioplasty, debridement, and tendon repair are effective.