Objective: This study was designed to evaluate the efficacy of balneotherapy which includes mud pack therapy in patients with subacromial impingement syndrome (SIS). Material and Methods: 29 patients (23 females, 6 males) with shoulder pain for more than three months who were diagnosed as SIS were included in this study. The mean age was 48.24 ± 6.83 (33-60) years. Mud pack therapy was applied at 45°C for 30 minutes, and the therapy continued once a day, for15 days. Visual Analog Scale (VAS) scores for pain evaluation during rest, activity and night, and Constant, UCLA and Shoulder Disability Questionnaire (SDQ) scoring for the functional situation were used as outcome measurements. All patients were instructed to perform Codmans pendulum, passive strengthening and range of motion (ROM) exercises as home exercises during the study. Besides, the patients took paracetamol when needed. Results: All parameters were evaluated three times (before therapy, after therapy and at the end of third month). VAS, Constant, UCLA Score, SDQ scores were improved significantly. Conclusion: We concluded that balneotherapy can be safely applied for patients with SIS because it gives satisfactory results in early period and improves the quality of life for these patients.