Cystic hygroma is a benign neoplasm of developmental origin. It is best treated by surgical excision soon after recognition in order to prevent extensive local growth and expansion which can encroach on vital structures such as nerves, major vessels, and the trachea. Surgical resection should be complete when possible. Vital structures should be preserved, however, even at the expense of incomplete excision. This study of 15 cases emphasizes the origin, clinical features, and therapy of cystic hygroma.