Abstract: The objective of the present study was to evaluate the relationship between subacromial distance measures before and after Arthroscopic Subacromial Decompression (ASD) using MRI and clinical status in patients with chronic impingement. Forty patients with chronic impingements at stage two and three were evaluated using UCLA shoulder scale and the Constant-Murley shoulder assessment and their subacromial distances were measured using MRI before ASD. They were monitored for 27.3 months (12-48) after ASD. The same evaluations and measurements were obtained at the end of the follow-up period. The initial and final subacromial distances were different (8.32 (5-12) vs. 11.90 (8-14) mm, respectively). The Constant-Murley shoulder assessment and UCLA shoulder scale scores also increased from 15.55-72.40 and from 8.10-30.95, respectively. Wilcoxon signed rank test confirmed statistical improvement in all these variables upon ASD (p<0.05). In this study, clinical remission was associated with the subacromial distance elongation in patients with chronic impingement upon ASD.