Goiter prevalence and iodine excretion levels were assessed in schoolchildren aged 9 and 13 in the city of Moscow (n = 91) and the Moscow region, 60 km East of Moscow (n = 92). Goiter prevalence was evaluated by ultrasonography. In Moscow it was found to be 31.1% among children aged 9 and 17.5% among those aged 13. The respective values in the Moscow region were 47.2 and 39.3%. Medium urinary iodine levels were 6.9 to 7.5 micrograms/dl in Moscow and 4.1 to 5.4 micrograms/dl in the region. According to modern criteria, iodine deficiency in Moscow may be regarded as mild and in the region as moderate. Control programs are urgently needed tc prevent development of iodine deficiency disorders.