Casual urine samples were collected to determine iodine excretion of 1680 Belarus children during 1990-1994. The subjects, 8-16 years old, were from nine different regions of Belarus; 60% were from the Gomel oblast, which has been associated with relatively high levels of radioiodine fallout and increased incidence of thyroid cancer. Most of the median values indicate borderline/low iodine intake or mild iodine deficiency. Ranges were wide but 163 children excreted < 20 micrograms I/l urine and they should be considered severely deficient in iodine.