From 1975 through 1988, 11 cases with accessory nerve injury were admitted to our hospital. The etiology in 9 of these cases was inadvertent surgical injury during operation. In the other 2 cases it was injured in accidents. The typical clinical manifestations of paralysis of the trapezius muscle and disorder of the shoulder movement were all seen in our cases. The diagnostic features, indications for operation, surgical technics and criteria for efficacy assessment were discussed. The necessity of early operation was stressed, and either neurorrhaphy or neurolysis should be done.