Objective:To evaluate the methods of diagnosis and treatment of thyroid disease with concomitant focal lymphocytic thyroiditis(FLT), and explore the reasons for its confused with Hashimoto′s disease(HD).Methods:During the recent 25 years, 207 patients underwent surgical trearment for pathologically diagnosed HD.Among this group, 143 cases of HD with other concomitant thyroid disease were retrospectively analysed.Results:Of the 143 cases, 57 cases were found to have thyroid disease with concomitant FLT, and this was 27.5%(57/207) of the total HD group, or 39.9%(57/143) of the group with thyroid disease and concomitant HD.Intraoperative pathologic section revealed that focal lymphocytic infiltration was positive in 87.7%(50/57) of cases. The postoperative hypothyroidism occurrence rate was 19.3%(11/57), of which, 7 cases(7/57, 12.3%) were subclinical hypothyroidism.Conclusions:The character of pathologic changes of thyroid disease with FLT and with HD was different. Intraoperative pathologic section can be helpful in the diagnosis of this condition and can have important significance as a guide to the scope of surgical resection of the thyroid gland.