PURPOSE: The purpose of this study was to evaluate the results of surgical treatment in patients with chronic flexor carpi ulnaris tendinopathy. MATERIALS AND METHODS: Five patients with 7 wrists underwent surgical treatment for chronic flexor carpi ulnaris tendinopathy. The degenerative tissue inside the tendon over the pisiform was debrided and partial release of the tendon was performed. The clinical outcome was evaluated using pre and postoperative visual analogue scale (VAS) pain score and modified Mayo wrist score at the final follow-up. RESULTS: The mean VAS score was 7.3 preoperatively, which was significantly improved to 3.6 at postoperative 2 weeks, 1.9 at 6 weeks, 1.1 at 3 months, 0.7 at 6 months, and 0.7 at the final visit. Modified Mayo wrist score showed 3 excellent, 3 good, and one fair result. Biopsy showed degenerative tissue findings in all cases. CONCLUSION: Chronic flexor carpi ulnaris tendinopathy is a degenerative disease and surgical treatment of refractory cases can decrease clinical symptoms in the early postoperative period and enable patients to return to activities of daily-living.