Cubital tunnel syndrome (CTS) is the second most common compression mononeuropathy that is effectively treated. The risk factors for CTS include repetitive arm flexion at the elbow joint and prolonged arm flexion with support on the elbow. The diagnosis of CTS is based on its clinical presentations, the data of neurological examinations, and the results of electroneuromyography and ultrasound examination. The symptoms of the disease progress quickly, therefore the early diagnosis of CTS and its timely treatment are of great importance for the patient's recovery. Unfortunately, patients with CTS are often observed to be erroneously diagnosed with degenerative and dystrophic spinal changes. The paper presents an observation of effective treatment in a young patient who has been suffering from CTS for a long time and been erroneously diagnosed with spinal osteochondrosis. Six months after surgical treatment (for decompression and neurolysis of the left ulnar nerve), the patient regained hand sensitivity and movement. It is concluded that further investigation is necessary to assess predictors of effective surgical treatment in patients with this disease.