Abstract: In this study initially consecutive patients with Autoimmune Thyroiditis (AT) were taken in the Endocrinology Polyclinics. Beside that age and sex-matched patients with HCV infection and control cases were randomly studied in the Gastroenterology and Internal Medicine Polyclinics, respectively. One hundred and seventy-two patients with AT, 62 with HCV infection and 110 control cases were studied. AT was diagnosed in eight (12.9%) cases of the HCV infecteds’ group and this ratio was 11.8% (13 cases) in the control group (p>0.05). Similarly, HCV infection was detected in one (0.5%) case of AT group and this ratio was 0.9% (one case) in the control group (p>0.05). Parallel to these results, prevalences of antithyroid peroxidase and/or antithyroglobulin antibodies were detected as 29.0% (18 cases) and 32.7% (36 cases) in the HCV infecteds’ and control groups, respectively (p>0.05). As another face of the results, it was detected one case of monoclonal gammopathy of undetermined significance and one case of lichen planus in the HCV infecteds’ group. As a conclusion, HCV infection may be associated with autoimmune disorders and malignancies but not with AT.