Cubital tunnel syndrome represents the second most common compression neuropathy in the upper limb. There are three main surgical procedures to deal with this issue, namely simple decompression, medial epicondylectomy and anterior transposition. Nevertheless, optimal surgical treatment is still open to question. In the past three years we performed decompression of the nerve with or without external neurolysis and epineuriotomy on 52 patients (55 extremities). Preoperative diagnostic procedures included functional hand status, neurophysiological evaluation, X-ray of the elbow and neurosonography. Patients were then divided into three groups according to the staging criteria of Dellon. After an average follow-up of 13 months, the outcome was evaluated by complete examination of hand function, electrophysiological studies and interview with the patients. Postoperatively, two-point discrimination as well as strength improved significantly. Postoperative grip was 28.78 kg (79.8 % of the other hand), compared to 20.31 kg (58 % of the other hand) preoperatively (p = 0.000). Evaluation of each stage individually showed that the best functional outcome was achieved by the minimum-staged group with improvements in strength and sensory in all patients and total relief in two-thirds. In the severe-staged group, improvement could still be found in 75 % of the patients. Evaluation of conduction velocities showed highly significant improvements for both motor and sensory conduction velocities. In summary, simple decompression, if necessary modified with external neurolysis and epineuriotomy, showed high success rates in all stages. Decompression is a minimally invasive procedure, but very effective for mild as well as for severe cases and therefore the optimal treatment in cubital tunnel syndrome.