Purpose: The purpose of this study was to evaluate the surgical outcome of arthroscopic removal of intraosseous deposits in calcifying tendinitis of the rotator cuff. Methods: We studied the results of arthroscopic treatment in 30 shoulders in 28 patients with calcifying tendinitis (mean age, 48.3 years; age range, 26 to 83 years), with a mean follow-up of 38 months. According to the localization of calcification, the patients were divided into 2 groups: those with pure tendinous/soft-tissue involvement (n = 25) (group I) and those with tendinous/soft-tissue and osseous involvement (n = 5) (group II). After routine tendon debridement, debridement and curettage of the bone lesion were also performed in patients with bone involvement. Clinical outcome was evaluated by use of the pain score on a visual analog scale and the Constant score, and a special inquiry was used for self-assessment. Results: The pain scores and functional Constant scores improved significantly after the operation in both groups (P=.043 for pain score and P=.0001 for Constant score in group I and P=.042 for pain score and P=.0001 for Constant score in group 11). The median Constant score increased from 42 (range, 22 to 65) preoperatively to 100 (range, 80 to 100) postoperatively in group 1 and from 40 (range, 25 to 55) to 100 (range, 85 to 100) in group II. The mean pain score was 6.5 +/- 1.4 (range, 4 to 9) before treatment and 0.2 +/- 0.5 (range, 0 to 2) at follow-up in group 1, and it was 6.2 +/- 1.48 (range, 4 to 8) and 0.4 +/- 0.55 (range, 0 to 1), respectively, in group II. There was no significant difference between the 2 groups in terms of the final Constant (P=.85) and pain scores (P=.26). Conclusions: Arthroscopic removal of intraosseous and intratendinous deposits to treat calcifying tendinitis with osseous involvement seems to be as safe and effective a treatment method as the arthroscopic removal of intratendinous deposits in cases of tendinous involvement only.