The outcome of 185 reoperations between 1986 and 1995 could be grouped into three categories: 1. In 91 cases (49.2%) the retinaculum was not fully divided (in most cases distally) or was completely intact. Most of these patients presented atypical incisions and deterioration of distal motor latency as well as worsening of the clinical symptoms. 2. In 58 cases (31.4%) true recurrences were present. Forty-five of these patients received chronic haemodialysis. 3. In 36 cases (19.5%) the reoperation proved unnecessary. In ten of them iatrogenic nerve damage was found. Five patients were assumed to have spontaneous intraneural bleeding following decompression of the highly compressed nerve with prolonged recovery. Other cases presented additional symptoms of radicular compression ("double crush syndrome"), especially when the electroneurographic findings were discrete or could not be compared with preoperative values. With regard to these experiences, reoperation is indicated when symptoms of median nerve compression persist, especially when an atypical incision is present and distal motor and sensory latency has increased. True recurrences are rare, except in patients undergoing chronic haemodialysis. Reoperation has proved to be less successful in patients presenting atypical signs and symptoms, e.g. dysaesthesia following the first operation, which is rather typical for nerve damage, or a double crush syndrome. Exploration is also not indicated in patients suffering from tender scars. Since additional intraneural neurolysis is unnecessary, reoperations can be performed under local anaesthesia in bloodless field.