In this study, we analyzed the results of two series of patients treated for impingement syndrome by undergoing arthroscopic subacromial decompression (ASD). Patients had not responded to nonoperative treatment. Group 1 included 112 consecutive patients (average age, 41 years) with 96 (77%) patients available for 2-year follow-up. Group 2 (28 patients, 29 shoulders; average age, 43 years; range, 22 to 72) had ASD and the subacromial space digitally palpated to determine if adequate decompression was performed. Twenty-two (85%) of 26 shoulders were available for follow-up. At follow-up, pain, function, range of motion, strength, impingement signs, and patient satisfaction were assessed. In group 1, according to the Neer criteria, 48% of the patients were graded as satisfactory and 52% unsatisfactory. Workers' Compensation patients had a satisfactory rate of 32%, whereas non-Workers' Compensation patients had a satisfactory rate of 59%. Twenty patients had open acromioplasty after ASD. Inadequate decompression was noted in 14 of 20 failed patients. In group 2, 86% of the patients were graded as satisfactory according to the Neer criteria, with 14% unsatisfactory, which included the 2 failures. The 2 (9%) of 22 shoulders that failed the ASD went on to further surgical treatment. Average follow-up was 56 months (range, 13 to 78 months). The average American Shoulder and Elbow Society score at follow-up was 90.4. No difference between Workers' Compensation cases and the other cases was seen (P <.7). Finger palpation can help to improve outcomes by allowing the surgeon to assess the adequacy of decompression.