The median urinary iodine concentration (UIC) for schoolchildren was 90 microg/L in Biella and 136 microg/L in Novara in survey carried out in 1995-1996. Biella resulted as iodine deficiency area and Novara as iodine sufficient area. Aim of our study was to assess goiter prevalence by ultrasonography in Biella and Novara schoolchildren and to evaluate median UIC in Biella schoolchildren.A total of 829 Biella schoolchildren and 310 Novara schoolchildren, aged 7-15 years, were submitted to thyroideal ultrasonography. Biella schoolchildren were submitted to morning-spot urine sample's collection for UIC's determination.The ultrasound goiter prevalence as function of age resulted 15.7% in Biella and 14.8% in Novara (P = 0.7, chi 2 test). The ultrasound goiter prevalence as function of body surface area resulted 17.1% in Biella and 7.1% in Novara (P < 0.0001, chi 2 test). UIC (25-75 degrees ) for Biella schoolchildren who attended third and fifth year of primary school was 159 microg/L (107-228 microg/L) while for Biella schoolchildren who attended second year of secondary school was 150 microg/L (92-218 microg/L).Based on the results of UIC, Biella is considered as iodine sufficient area. Based on the results of goiter prevalence by ultrasonography, both Biella and Novara resulted as iodine deficiency area. UIC and goiter prevalence, however, provide different informations about iodine status: UIC supplies informations about present iodine status while goiter prevalence assesses past iodine status.