Nodular thyroid pathology weighs heavily for 4-5% of the general population, being the most common among the endocrinopathies. Because of this these diagnostic methods have gained more and more importance as FNA able to select already in the pre-operation phase the malignant nodules from the benign ones and to decide on the most suitable surgical intervention. In the period of time between January 1989 and June 1992 in the Institute of the III Surgical Clinic in Rome there have been performed 403 FNA. From the whole total we have extrapolated 221 patients. In this study we stressed how the FNA method has a sensibility of 80%, a specificity of 93% and afterwards an accurate diagnosis of 92%. Besides we have verified that sonography and radionuclide scanning have a truth worthiness respectively of 64% and 52%. The FNA in our opinion allows us to have in the pre-operation phase a much more accurate diagnosis as regards that obtained with only sonography and radionuclide scanning therefore the latter methods must be considered complementary to FNA.