Background: The term “incidental" denotes malignant tumors of the thyroid gland detected postoperative in surgical specimens resected for benign disease. As cancer, thyroid is the commonest endocrine malignancy and their incidence increases over the past 15-20 years. In Egypt, it represents 2.2% of total cancers. It constitutes 30% of endocrine malignancies and 12-49% of head and neck tumors. Objective: The aim of this study was to determine the incidence and histological features of incidental cancers in patients who had total thyroidectomy for benign thyroid diseases. Patients and Methods: This Study is a prospective, empirical study carried out at Al-Zahraa University Hospital during the period from April, 2016 to April, 2018. The study included 100 cases had total thyroidectomy of previously diagnosed benign thyroid diseases and fulfilled the inclusion criteria. Results: In this study, 100 patients underwent total thyroidectomy. The female (n=86) to male (n=14) ratio was 6.14: 1 and the age ranged from 19 to 69 years. The incidental carcinoma in this study found in 12 (12%) patients. The frequency of papillary carcinoma was 9 % of all thyroid diseases and 75% of the incidental thyroid cancer (ITC) (9/12). Also, frequency of follicular carcinoma was 1.4% of all thyroid diseases (three cases) and 16.66% of the ITC. Conclusion: The non-irrelevant incidence of ITC, the eventuality of multifocal and bilaterality and the possible occurrence of relapse support that total thyroidectomy without residuum is a valuable option for treating benign thyroid conditions.