BACKGROUND: Both open ulnar nerve decompression and retractor-endoscopic ulnar nerve decompression have been shown to yield good results. However, a comparative evaluation of the techniques is lacking. OBJECTIVE: To compare the results of open and endoscopic surgery in cubital tunnel syndrome. METHODS: One hundred fourteen patients undergoing open (n = 59) or endoscopic (n = 55) decompression of the ulnar nerve for cubital tunnel syndrome were retrospectively compared. The long-and short-term outcomes were compared with respect to the time until return to full activity and the duration of postoperative pain. Additionally, matched pairs between the 2 groups were chosen for analysis (n = 34). RESULTS: Long-term results in the open vs endoscopic groups were as follows: excellent results, 54.2% vs 56.4%; good results, 23.8% vs 32.7%; fair results, 20.3% vs 9.1%; and poor results, 1.7% vs 1.8%, respectively. For the matched pairs, the results had similar significance levels (P =.84). The times until return to full activity in the open vs the endoscopic groups were as follows: 2 to 7 days, 18.6% vs 76.4%; 7 to 14 days, 55.9% vs 10.9%; and > 14 days, 25.4% vs 12.7% (P <.001 between nonmatched and matched pairs). The durations of postoperative pain in the open vs the endoscopic groups were as follows: 1 to 3 days, 45.8% vs 67.3%; 3 to 10 days, 42.5% vs 25.4%; and > 10 days, 11.7% vs 7.3% (P =.04 for nonmatched and P =.05 for matched pairs). CONCLUSION: There are no significant differences in long-term outcomes after open and retractor-endoscopic in situ decompression of the ulnar nerve in cubital tunnel syndrome. The short-term results are significantly better in endoscopic surgery.