Introduction: Thyroid nodules are very frequent in the general population, affecting about 6% of adult women and 2% of men. An accurate ultra-sonographic evaluation shows that approximately two thirds of all women and one third of all men have small nodules in their glands. True simple thyroid cysts originating from benign epithelial cells are rare. Most cystic nodules are partially solid structures with cystic degeneration (mixed or complex nodules). The clinical-laboratory characteristics of solid or complex thyroid nodules are well known because of their possible association with malignancy, but the characteristics of simple cystic nodules have not been fully determined. Material and methods: The study was conducted on 225 patients with thyroid nodules (18 men and 207 women) ranging in age from 18 to 87 years who were divided into 4 groups: GROUP 1-patients with SIMPLE CYSTS, GROUP 2-patients with SIMPLE CYSTS associated with SOLID NODULES, GROUP 3-patients with PURE SOLID NODULES, and GROUP 4-patients with COMPLEX NODULES. TSH, free T4, free T3, Thyroglobulin, Anti-Thyroperoxidase Antibody, Anti-Thyroglobulin antibody and Anti-TSH Receptor Antibody (TRAB) were determined. Results and discussion: SIMPLE CYSTS were not infrequent in the population studied. Single SIMPLE CYSTS occurred in a younger population compared to the remaining types of nodules. SINGLE SIMPLE CYSTS were less frequent than SIMPLE CYSTS associated with SOLID NODULES .SINGLE SIMPLE CYSTS, cysts associated with SOLID NODULES and COMPLEX CYSTS were found to be all benign in the present study. Conclusion: COMPLEX CYSTS were the most frequent nodules and also the largest among these patients. Anti-TPO, Anti-Tgand Thyroglobulin levels were higher in patients with SIMPLE CYSTS associated with Clinical Hypothyroidism and Hashimoto Thyroiditis. The single case of thyroid carcinoma was detected here in a single Solid Nodule.