Diagnosis of adhesive capsulitis is a clinical diagnosis based on history and physical examination. Afflicted patients exhibit active and passive loss of motion in all planes and a positive capsular stretch sign. The effect of adhesive capsulitis on acromioclavicular biomechanics leading to tenderness has not been documented in the literature. This study reports on the incidence of acromioclavicular tenderness in the presence of adhesive capsulitis. Furthermore, we note the natural history of such acromioclavicular joint pain in relation to that of adhesive capsulitis. Over a 2-year period (2005-2007), 84 patients undergoing initial evaluation for adhesive capsulitis were prospectively examined with the use of validated outcome measures and physical examination. Acromioclavicular joint tenderness results were compared and analyzed on initial evaluation and final follow-up of at least 1 year. Forty-eight patients (57%) with adhesive capsulitis had acromioclavicular joint pain on examination. At final follow-up, as range of motion improved, a significant increase in American Shoulder and Elbow Surgeons/Penn shoulder score and decrease in number of patients with acromioclavicular pain was noted with only 6 patients with residual pain (P<.05). In the presence of adhesive capsulitis, there is not only compensatory scapulothoracic motion but also acromioclavicular motion. This often results in transient symptoms at the acromioclavicular joint, which abate as the frozen shoulder resolves and glenohumeral motion improves. This is important to recognize to avoid unnecessary invasive treatment of the acromioclavicular joint when the patient presents with adhesive capsulitis.