Abstract: Objective: To study the expression of uteroglobin-related protein 1 (UGRP1) in thyroid diseases and its clinical significance. Methods: Eighteen cases of normal thyroid tissue, 23 cases of nodular goiter, 35 cases of thyroid adenoma, 64 cases of Hashimoto's thyroiditis, 43 cases of Graves disease and 32 cases of thyroid carcinoma were involved in he study. Immunohistochemical method (Envision method) was used to detect the expression of UGRP1. Results: UGRP1 was not expressed in nodular goiter or thyroid carcinoma. The positive expression of UGRP1 in normal thyroid tissue, thyroid adenoma and Graves was 5.56%, 2.86% and 9.30% respectively. There was no significant difference among them (P>0.05). UGRP1 was strongly expressed in Hashimoto's thyroiditis, and the rate of positive expression of UGRP1 was 71.88%. The difference was significant between Hashimoto's thyroiditis and other thyroid diseases (P<0.01). Conclusions: UGRP1 is not expressed in nodular goiter or thyroid carcinoma, and weakly expressed in normal thyroid tissue, thyroid adenoma and Graves disease, but strongly expressed in Hashimoto's thyroiditis. UGRP1 is probably involved in the pathogenesis of autoimmune thyroid disease via immunity and inflammation, and may play an important role in the diagnosis and differential diagnosis of Hashimoto's thyroiditis.