Several researchers have suggested a possible relationship between nitrate intake and the development of goiter in children. The present cross-sectional study included schoolchildren between the ages of 11 and 14 years from 2 villages in Bulgaria with high and low nitrate levels in drinking water. The comparison between the median urinary iodine levels of the total number of exposed (179.0 microg/l) and nonexposed (202.50 microg/l) children showed statistically significant differences. The relative risk for the children exposed to high nitrate levels in drinking water, expressed as the odds ratio, was 8.145 (95% confidence interval = 1.67-39.67). The authors considered this to be very significant. They found a statistically significant difference for the prevalence of goiter among the exposed and nonexposed children. The results of the study confirmed the role of high nitrate levels in drinking water as a health risk factor for thyroid dysfunction.