The aim of this study was to evaluate the usefulness of fine-needle aspiration cytology (FNAC) and (99m)Tc-pertechnetate scintigraphy (TS) together in patients with differentiated thyroid carcinoma. Data from a series of 357 patients (284 women and 73 men, median age 43 years, range 19-73) with solitary thyroid nodule and no signs of hyperfunction, who had undergone both FNAC and TS prior to surgery, were retrospectively reviewed. FNAC distinguished 3 groups of TN (benign, follicular neoplasm, cancer), while patients with 'cold' TN were considered at risk of having a thyroid tumor. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were: 95%, 21%, 20%, 95% and 34% for TS; 82%, 99%, 96%, 96% and 96% for FNAC; 98%, 99%, 97%, 98%, and 99% for TS and FNAC together, respectively. In conclusion, patients with 'cold' TN and FNAC suggesting follicular neoplasm should be considered at risk of having cancer.