Background: Thyroid lesions are fairly common in and around Kolar town. This study was undertaken to study the various histomorphological types of neoplastic and non-neoplastic lesions of the thyroid and to correlate these with respect to age and sex. Methods: All thyroid specimens received at the pathology Department of Sri Devaraj Urs Medical College, Kolar during the period January 2000 to December 2004 were processed. A detailed histomorphological study was done. The histomosphological type was correlated with the age, sex and clinical presentation. Results: Total 120 cases of thyroid were studied. Most common age group affected was between 3rd and 5th decade. Females were predominantly affected. The non-neoplastic lesions reported in this study were thyroglossal duct cyst 1 case (0.83%), De Quervain thyroiditis 1 case (0.83%), Hashimoto thyroditis 11 cases (9.16%), colloid goiter 7 cases (5.83%), multinodular goiter 35 cases (29.16%), diffuse toxic goiter 2 cases (1.66%). Among neoplastic lesions follicular adenoma 43 cases (35.83%), atypical follicular adenoma one case (0.83%), papillary carcinoma classic variant 11 cases (9.16%), follicular variant of papillary carcinoma 7 cases (5.83%) and one case (0.83%) of medullary carcinoma. Conclusion: Total 120 thyroid lesions were studied in the present study out of this 57 cases were non-neoplastic and neoplastic were 63 cases. Sub–acute thyroiditis reported was 0.83%. Studies conducted by others range from 0.15% to 4.25%. Hashimoto thyroiditis reported was 9.16%. Other studies range from 4.25% to 5.68%. Colloid goiter reported was 5.83%. Reports of others range from 49.18% to 36%. Multinodular goiter reported was 29.16%. Other studies reported range from 3.19% to 18%. Diffuse toxic goiter reported was 1.66%. Other study reported incidence of 2.12%.