AbstractAim: To investigate the range of cytopathological abnormalities seen in thyroid lesions in a tertiary care hospital.Material and Methods: This study was conducted in the department of pathology, NMCH Patna, Bihar, Indiafrom June 2019 to May 2020. A total of 801 thyroidectomy specimens received in the histopathology laboratory,were included in the study. All biopsies were fixed in formalin and embedded in paraffin. The sections werestained with haematoxylin and eosin. Special stains like Congo Red, Periodic acid Schiff and reticulin were usedwhenever needed. After pathological diagnosis, the demographic data and final report were systematically enteredinto the register. The biopsy registers were reviewed and different lesions were categorized. Age and sex-wisevariations of the lesions were noted.Results: Multinodular goiter is the most common non-neoplastic thyroid lesion (71.5%) followed by thyroiditis.There were only 6 cases of toxic goiter among all the thyroid lesions received. Among the 801 thyroid lesions,there were 151 carcinomas (18.8%). Maximum numbers of carcinomas are seen in age group 31-40 with 43 cases,followed closely by fourth decade. There were no thyroid malignancies upto second decade. The numbers ofmalignancies were very minimum above 70 years (2.7%). The frequency of carcinomas among the total thyroidlesions is almost same for both males and females (18.82% and 18.85%). Papillary carcinoma was the mostfrequent malignancy, out of which half were of the micropapillary subtype. One of the thyroidectomy specimensshowed two different primary malignancies (follicular carcinoma and papillary micro carcinoma). Anaplasticcarcinoma was seen in only one thyroidectomy specimen. There was one metastatic thyroid carcinoma from aprimary lung carcinoma.Conclusion: Multinodular goiter was found to be the most common thyroid lesion in this study. The percentageof malignant thyroid tumors was high compared to other studies done in Bihar. Papillary carcinoma was the mostcommon malignant neoplasm. The micropapillary variant comprised 50% of the papillary carcinoma.