Lymphatic malformation is a benign single or a multi-cystic neoplasm of developmental origin that may occur throughout the body with the head-and-neck region being the most common site. For many years, a surgical excision has been the treatment of choice in the management of the lymphatic malformations. However, complete excision is difficult and the recurrences are common because the lymphatic malformations tend to infiltrate the surrounding tissues. The bleomycin injection therapy was performed in 10 patients with lymphatic malformation. The diagnosis was made by computed tomography(CT) or magnetic resonance image(MRI). All patients had cystic lesions greater than 5 cm in size. Tracheostomy was done before bleomycin injection in three cases because of obstructive dyspnea. Bleomycin was repeatedly injected in each patients between 3 and 7 courses. In all patients, the mass involuted variably and there were no significant complications such as fever, diarrhea and vomiting after injection.