Background: The diversity of diseases affecting the thyroid gland can be due tornhormonal excess/deficiency, reactive proliferations to deficiency states,rninflammation, or neoplastic conditions most of which manifest by a form ofrnenlargement of the thyroid gland commonly called goiter.rnThe distribution of these diseases depends on several factors, bothrnenvironmental and individual. Simple (non toxic goiter is quiet commonrnthroughout the world and is more prevalent where iodine difficiency isrnprevalent. The reported prevalence of goiter in Ethiopia is in the range of 27% inrnthe early 90s to 40% today.rnObjective: To assess the distribution of histolpathologic types of thyroidrndiseases over a period of four years.rnSetting: Tikur Anbessa Specialized Hospital, Department of Pathology,rnCollege of Medicine and Health Sciences, Addis Ababa UniversityrnMethods: Retrospective analysis of biopsy diagnoses of thyroid disease.rnResults: one thousand two hundred cases were included in the study. ninernhundred eighty six were found to be non neoplastic(82%) and two hundredrneleven were found to be neoplastic(18%). Nodular colloid goiter was therncommonest, appearing in 956 cases(79.6%). Adenoma, carcinoma andrnthyroiditis accounted for 64(5.3%), 147(12.3%) and 16(1.3%)respectively.rnThe female to male ratio was 5.1:1. Eighty four point five percent of thyroidrndiseases were found in the age group between 20 and 59 years.rnConclusion: Nodular colloid goiter is the commonest of all thyroidrndiseases. Thyroid malignancies have become more common thanrnadenomas. Papillary carcinoma is the commonest of thyroid cancers.rnEfforts need to improve to tackle the problem of iodine deficiency. Properrnevaluation of thyroid swellings and early seeking of health service in casernof neck swelling needs to be advocated.