Generalized lymphangiomatosis is a rare disease that is characterized by widespread bony and soft tissue involvement of lymphangioma. Radiological evaluation is crucial because the site and extent of the lymphangioma are important prognostic factors. We reported here on three cases of generalized lymphangiomatosis and all three cases showed similar radiologic findings, but a different clinical course. The CT, US and MR images showed sharply defined, nonenhanced cystic lesions involving the mediastinum, bones, spleen, lung and lower neck. The whole body MR imaging with the short tau inversion recovery (STIR) sequence showed good capability for evaluating the extent of disease.