Background: Twenty years ago, Pirque was a zone with a goiter prevalence of 39%. Aim: To assess the effects of salt iodination on the prevalence of goiter in school-age children of this zone. Subjects and methods: School age children from four public school in Pirque were examined, following WHO criteria for the diagnosis of goiter. Urinary iodine excretion was also measured. Results: Five hundred ninety one males and 298 females aged 12.1 +/- 2.5 years were examined. Fifty seven children (9.6%) had goiter. In 53 the goiter was grade I and in 4, grade II. No sex differences were observed. Minimal and median urinary iodine excretion values were 12.6 and 57.6 mu g/dl respectively. Conclusions: Goiter prevalence dropped from 39 to 10%. The fact that iodine intake is over minimal recommendations, underscores the effectiveness of salt iodination.