Cystic hygroma is a benign neoplasm of developmental origin. It is thought to arise from failure of the lymghatic system to communicate with the venous system in the neck. The most prominent sign of cystic hygroma is the presence of a mass which is painless and flutuant. A large cyst can cause. respiratory obstruction or swallowing difficulties. For many years, surgical excision has been considered as the treatment of choice. However, excision of the tumors, if incomplete, may readily be followed by lymphorrhea, wound infection or recurrence. Bleomycin given by local injection has drawn attention as an efficacious nonsurgical measure against residual or recurrent tumors. In this case we administered Bleomycin to the patient who had been failed to the surgical excision after tapping of the cyst by aspiration with a puncture needle. There was no serious side effect with Bleomycin injection and the size of the mass has became reduced.