Background: ulnar impaction syndrome (UIS) is a common cause of ulnar-sided wrist pain. The differential diagnosis of ulnar-sided wrist pain is diverse due to the complex nature of the bony and soft tissue anatomy UIS may lead to degenerative lesions of the triquetrum, lunate, ulnar head cartilage or of the TFCC. Concomitantly the triquetrolunate ligaments may be disrupted. Associated factors of ulno-carpal joint space narrowing may include previous fracture (e.g. of the distal radius), premature physeal arrest of the distal radius or congenital ulna positive variance. Aim of the work: this study aimed to evaluate the outcome of treating ulnar impaction syndrome with ulnar shortening osteotomy upon clinical and radiological. Materials and Methods: in this study ten adult patients with ulnar impaction syndrome were selected from Orthopedic Outpatient Clinic of Faculty of Medicine (Damietta), Al-Azhar University Hospital from January 2018 to October 2018 and they were operated by ulnar shortening osteotomy and fixed by plating.Description of technique alongitudinal incision over the subcutaneous border of the ulna issued to expose the ulna between the distal and middle third of the ulna from the ulna styloid. Preoperative posteroanterior (PA) X-rays were reviewed to determine the amount of shortening required, with a goal of creating -2 mm variance postoperatively. A 6-hole dynamic compression plate was predrilled distally prior to performing two oblique osteotomies separated by the desired shortening length. The fragments were reduced and plated by using compression. Results: the mean disabilities of the arm, shoulder and hand (DASH) score was 9 postoperatively. Flexion, extension and supination were reduced compared to the contralateral unaffected extremity (84.6%, 85.3%, and 86.9% of normal). Patients received worker's compensation 5 of 10 patients required hardware removal for plate irritation and 2 of 10 patients had a nonunion. Conclusion: we preferred our surgical technique ulnar shortening osteotomy for all cases of UIS. Pain was significantly improved in our Cases; however, smokers had less improvement in pain and higher disability scores.