Pediatric lymphangioma can occur at any site. However the neck is the most common site. There are two treatment modalities (surgical excision and intralesional injection) for lymphangiomas. But, the treatment guide line for lymphangioma has not been established, yet. The aim of this study is to establish the treatment guide line based on our experience with lymphangiomas. Medical records of 82 cases of lymphangioma were reviewed retrospectively. On MRI (magnetic resonance image) findings, lymphangiomas were divided into 4 groups by the proportion of the cyst bigger than 2 cm in diameter of the tumor; group A-proportion of cyst occupies more than 75 %, group B-proportion of the cyst 50~75 %, group C-25~50 %, and D in less than 25 %. All patients were treated with OK-432 intralesional injection as the initial treatment. The effective response rates of OK-432 in group A & B were 88.2 % and 88.8 %, respectively. Group C response was 38.0 % and D only 20.0 %. Twenty-three patients received surgical excision. The result of surgical excision was generally satisfactory. Surgical site infection occurred in 1 case and postoperative bleeding in 1 case. Theses results indicate that intralesional injection of OK-432 could be the first line therapy in group A & B. In group C, OK-432 would be better as the first line therapy than surgery. For the group D, surgical excision should be the first line of treatment.