In Austria, a law stipulating that table salt should be iodized with 10 mg Kl/kg was introduced in 1963. Nevertheless, investigations carried out between 1982 and 1984 on iodine supply and goitre frequency revealed that there was a general iodine deficiency of first to second degree according to WHO criteria. These results led to an increase in salt iodization to 20 mg Kl/kg in 1990. The aim of the study was to determine iodine supply and thyroid volumes of schoolchildren 3 years thereafter. 734 children at primary and secondary schools were examined. The mean value of iodine excretion was 121 micrograms/g Cr, corresponding to an improvement in iodine intake. Compared to previous data, the corresponding age groups showed lower mean thyroid volumes.