Introduction: Considering the influence of geographical, genetic and ethnic factors on the prevalence of thyroid pathological lesions, this study was performed to assess the prevalence of pathological lesions in thyroid autopsic samples obtained from adult cadavers of Isfahan Forensic Medical Center. Material and Methods: In this study, 202 thyroid glands from cadavers with no evidence of thyroid diseases, removed during autopsies at Isfahan Forensic Medicine Center, were analyzed. After gross studies, thyroid glands were fixed in 5% formalin for 72 hrs, and then 3-6 sections were obtaind from each gland. Tissue sections were microscopically studied by two pathologists for histopathological lesions. Results: Among 202 thyroid glands (removed from 159 males and 43 famales), 131(64.85%) were histopathologically normal, and goiter (nodular, and diffuse), Hashimoto's thyroiditis, lymphocytic thyroiditis, follicular adenoma and papillary carcinoma were observed in 41 (20.3%), 10 (4.95%), 12 (5.94%), 2 (1.49%) and 12 (5.94%) of the thyroid glands, respectively. Twenty-six glands (12.23%) had nodules sized ≤ 1cm, which included 7 cases of occult papillary carcinoma (papillary micro carcinoma) and the prevalence was significantly different by sex (P<0.05). Conclusion: Clinically-normal thyroid glands may contain major pathological lesions when they are microscopically studied. Considering the high prevalence of thyroid malignancy and occult carcinoma in Isfahan County compared to other parts of the world, more attention should be paid even to the minor findings during clinical examination of thyroid gland.