Objectives: Simple decompression is an accepted surgical treatment of ulnar nerve entrapment at the elbow (UNE). Our purpose was to evaluate the outcome and potential predictors for the outcome after simple decompression in UNE. Methods: All surgically treated UNE cases (from 2004-2008) at our department were studied retrospectively. Out of 285 primary surgeries, 242 primary simple ulnar nerve decompressions were included. Medical records, including electrophysiologic protocols, were reviewed and postoperative outcome was graded: 1) cured/improved and 2) unchanged/worsened symptoms, based on surgeon-evaluated outcome. Results: Of the 242 simple decompressions (122 males and 120 females; median age 50.5 years), 101 cases were students, retired, un-employed, or on a long-term sick-leave and 112 had manual, blue-collar type of careers. 189 cases were cured or improved, while 53 cases had no change in, or even worsened, symptoms. Gender, presence of smoking, or associated diseases did not affect outcome, while a tendency was observed for higher age, a manual occupation and constant symptoms. Out of 196 cases electrophysiologically examined, 155 cases showed signs of ulnar nerve affection (56 reduced conduction velocity; 19 conduction block; 80 axonal degeneration; latter two groups significantly worse outcome). Conclusion: Patients with a preoperatively electrophysiologically diagnosed nerve conduction block or axonal degeneration have higher risk of not being cured or improved after simple decompression in UNE. Older patients, those with a manual profession, and constant symptoms of UNE tend to be less improved after surgery. [Hand Microsurg 2018; 7(1.000): 24-32]