The purpose of this study was to determine the incidence of clinically significant postoperative stiffness following arthroscopic rotator cuff repair. This study also sought to determine the clinical and surgical factors that were associated with higher rates of postoperative stiffness. Finally, we analyzed the result of arthroscopic lysis of adhesions and capsular release for treatment of patients who developed refractory postoperative stiffness 4 to 19 months (median, 8 months) following arthroscopic rotator cuff repair. A retrospective review of a consecutive series of arthroscopic rotator cuff repairs was conducted. During a 3-year time period, the senior author (S.S.B.) performed 489 arthroscopic rotator cuff repairs. The operative indications, technique of the rotator cuff repair, and the rehabilitation protocol were essentially unchanged during this time period. Demographic data, comorbid medical conditions, rotator cuff tear description, technique of repair, and concomitant surgical procedures were evaluated for their effect on stiffness. All office evaluations were reviewed to determine the pre- and postoperative motion, pain scores, functional strength, and patient satisfaction. Patients who were dissatisfied because of the development of postoperative stiffness underwent secondary arthroscopic lysis of adhesions. The final result of the secondary lysis of adhesions and capsular release were analyzed. In total, 24 patients (4.9%) were dissatisfied with the result of their procedure because of the development of postoperative stiffness, which was more likely (P < .05) to develop in patients with Workers' Compensation insurance (8.6%), patients younger than 50 years of age (8.6%), those with a coexisting diagnosis of calcific tendonitis (16.7%) or adhesive capsulitis (15.0%) requiring additional postoperative therapy, partial articular-sided tendon avulsion (PASTA) type rotator cuff tear (13.5%), or concomitant labral repair (11.0%). Patients with concomitant coracoplasty (2.3%) or tears larger in size and/or involving more tendons were less likely (P < .05) to develop postoperative stiffness. Among 90 patients positive for selected risk factors (adhesive capsulitis, excision of calcific deposits, single-tendon repair, PASTA repair, or any labral repair without a concomitant coracoplasty), 12 (13.3%) developed postoperative stiffness (P < .001). This overall clinical risk factor combined with Workers' Compensation insurance identified 16 of the 24 cases resulting in a sensitivity of 66.7% and a specificity of 64.5%. All 24 patients who experienced postoperative stiffness elected to undergo arthroscopic lysis of adhesions and capsular release, which was performed from 4 to 19 months (median, 8 months) after the rotator cuff repair. During second-look arthroscopy, 23 patients (95.8%) were noted to have complete healing of the original pathology. Following capsular release, all 24 patients were satisfied with the overall result of their treatment. In a series of 489 consecutive arthroscopic rotator cuff repairs, we found that 24 patients (4.9%) developed postoperative stiffness. Risk factors for postoperative stiffness were calcific tendinitis, adhesive capsulitis, single-tendon cuff repair, PASTA repair, being under 50 years of age, and having Workers' Compensation insurance. Twenty-three of 24 patients (95.8%) showed complete healing of the rotator cuff. Arthroscopic release resulted in normal motion in all cases. Level IV, therapeutic case series.