To confirm the predictive value of calcifications in thyroid nodules as a risk factor for malignancy and to detect specific aspects for tumours, in a set of 175 patients--30 papillary carcinoma (PC) and 145 multinodular goiters (MNG) with dominant nodule--calcifications were detected by ultrasound scan. Calcifications were significantly more frequent in PC than in MNG (40% vs 20.7% p < 0.05) but their considered characteristics (size, number, position, location in the gland, sonographic features of the nodule) did not show any particular difference between PC and MNG. The frequency of calcifications in our series was higher in older patients (mean age 58.7 +/- 13.3 vs 51.1 +/- 12.7 in patients without calcifications, p < 0.001) and this could imply that their onset is time-dependent. Calcifications can be a useful indicator of enhanced risk, to be considered in the overall process of surgical decision making.