There are several useful diagnostic examinations for thyroid disease. The diagnostic value of CT in thyroid disease is still contraversial, although CT has become a routine clinical examination, since the plain CT does not always identify tumors accurately. In this paper, we introduce for the first time thyroid lymphography-computed tomography (TLGCT) which may improve the diagnostic value of CT.The technique combines CT with thyroid lymphography (Matoba & Kikuchi, 1969).We performed TLG-CT in 92 patients with various thyroid diseases and 20 normal controls and classified the radiological features into the following 6 types: entire (normal thyroid); moth-eaten (Hashimoto's thyroiditis); defect (follicular adenoma and adenomatous goiter); lobate (papillary carcinoma); localized (various thyroid diseases); and extrathyroid defect (parathyroid tumor).In addition, we examined the relationship between TLG-CT type and the macroscopic appearance of the cut surface of the thyroid and lymph node metastasis in 20 patients with papillary carcinoma.The results suggest that papillary TLG-CT type carcinomas have a high incidence of lymph node metastasis.Our preliminary results suggest that TLG-CT is a potentially valuable diagnostic tool in the detection of thyroid disease and the assessment of the pathologic diagnosis as well as lymph node metastasis.