Objectives: A treatment protocol was developed for shoulder impingement syndrome in patients undergoing a major thoracic surgery and the results were compared with those of a control group. Methods: Treatment with steroids and local anesthetics was administered to 17 patients (15 males, 2 females; mean age 62 years; range 52 to 68 years) who developed impingement syndrome after coronary artery bypass surgery, and to 17 control patients (6 males, 11 females; mean age 56 years; range 43 to 67 years) who did not have thoracic surgery but had impingement syndrome. Injections were made subacromially, around the biceps tendon, intraarticulary, and in the posterior pericapsular area. After the injections, conservative therapy was given, which also included at least six weeks of the Jackins physical therapy program. The patients were assessed before and 3, 6, 9 and 12 months after the treatment with the use of the UCLA (University of California at Los Angeles) scoring system. Results: Before the treatment, the UCLA scores were poor in all the patients in both groups. The results of the treatment in the thoracic surgery group at the end of a year were excellent in 12 patients (70.6%) and good in five patients (29.4%). In the control group, five patients (29.4%) were rated as excellent, eight patients as good (47.1%), and four patients as poor (23.5%). Conclusion: Compared to controls, patients that develop shoulder impingement syndrome following major thoracic surgery benefit from steroid-local anesthetic injections and short-term conservative therapy with a far better response characterized by early relief of pain and rapid improvement in the shoulder range of motion.