Ulna-shortening osteotomy is a therapeutic option for ulnar impaction syndrome. We aimed to assess the long-term subjective and functional outcome after ulna-shorteming osteotomy. We conducted a retrospective study of 18 patients presenting with ulnar impaction syndrome of various aetiologies, with an average follow-up of 5.9 +/- 3.4 years. Seventeen patients (94.4%) were satisfied and would undergo the operation again. Although most patients reported residual complaints (833%) such as weakness (38%) or pain under given specific circumstances, objective measurements of wrist function were good. The average Mayo Wrist Score was 75.9 +/- 13.4 (n=16) and the average DASH score was 18.0 +/- 13 (n=12). Comparison of the operated and healthy limb did not show any significant difference in strength or range of motion, except for significantly reduced flexion on the operated side (p < 0.05). In this study, ulna-shortening osteotomy provided a good functional outcome and high subjective satisfaction over the long term.