The treatment of the established compartment syndrome in the forearm varies along the degree of the severity. We reviewed 17 cases of the established compartment syndrome in the forearm treated at Seoul National University Hospital from February 1979 to July 1985. Follow-up was performed more than one year in 14 cases. And the mean follow-up period was 30 months. Out of 17 cases operated on, mild involvement were found in 5 cases. Moderate and severe involvements were observed in 6 and 6 cases respectively. Tenolysis-tendon lengthening was done for 7 cases and proximal release (muscle-sliding operation) was performed in 8 cases. In two cases, living muscle and skin were transfered using microsurgical technique. In mildly to moderately affected, functional improvements can be obtained in most cases. The proximal release was superior to the tenolysis-tendon lengthening in this category of involvement. However, in severely involved group, the functional gain after the operation is slight in spite of the time consuming, difficult surgery including free muscle transfer. The neurological problems could be gradually improved without treatment in almost all cases.