INTRODUCTION Sulcus ulnaris syndrome is the second most common neurocompression syndrome in the upper limb after carpal tunnel syndrome. Its severity can be appreciated by the Dellon Classification. We present our experience and results after endoscopic decompression. PATIENTS AND METHODS A retrospective chart review of 55 patients operated over a 3-year period was performed. The patients, 37 men and 18 women, had an average age of 54 years (range: 27-82 years) at the time of surgery. The clinical diagnostic was always confirmed by a neurophysiological examination of the nerve conduction. According to the Dellon Classification, 11 patients had mild sulcus ulnaris syndrome, 31 had moderate and 13 had severe. The mean follow-up time was 21 months (range: 6-42 months). RESULTS The sensibility was normalised in 85% of the patients. Compared to the contralateral non-operated side, the mean grip strength improved from 68 to 94% and the mean pinch grip from 72 to 95%. The rate of nerve luxation did not change (5.5%). According to the modified Bishop rating system, 38 patients (69%) had excellent, 13 patients (23.5%) good and four patients (7.5%) fair results. One haematoma necessitating a revision, a minimal lesion of the ulnar nerve with restitution ad integrum and a hypoesthesia of the elbow, occurred after surgery resulting in a complication rate of 5.5%. Ninety-eight percent of the patients responded that they would undergo the endoscopic procedure again if needed. CONCLUSION Endoscopic decompression of the ulnar nerve in sulcus ulnaris syndrome is very well appreciated by patients and also provides promising clinical results.