According to previous studies, Turkey has generally been accepted as a moderate endemic iodine deficient country. However, it has recently been reported that there are regions in Turkey where iodine deficiency is more severe than previously known. The current study was aimed at ascertaining the goiter prevalence by thyroid volumes, iodine status and thyroid functions in school-age children living in an area which is suspected to have moderate or severe iodine deficiency. Overall goiter was found in 47.6% of children, in 22.8% of girls and in 24.8% of boys. Mean thyroid volumes did not differ significantly according to sex. Significant correlation was found between thyroid volume and body surface area and age. There was a negative correlation between the urinary iodine concentration and thyroid volume (r = 0.45, p < 0.01). Median urinary iodine concentrations in subjects with and without goiter were 20 microg/dl and 5.2 microg/dl, respectively. While median urinary iodine levels of the subjects with goiter were consistent with severe-moderate iodine deficiency, levels in subjects without goiter were comparable to moderate-mild iodine deficiency. None of the subjects had the signs or symptoms of hyper-or hypothyroidism. The differences in the mean values of thyroid hormones and TSH levels between subjects with or without goiter were not significant (p > 0.05). No correlation was found between urinary iodine concentrations and thyroid hormone levels. A weak correlation was found between urinary iodine concentration and TSH levels (r = 0.12, p = 0.05). Individuals with goiter were investigated etiologically: biochemical hypothyroidism was detected in 2%, compensated hypothyroidism in 12.6%, autoimmune thyroiditis in 2%, nodular goiter in 3% and isolated high TSH level with autoimmune thyroiditis in 0.08%. In conclusion, although a salt iodization program has been started in Turkey, our study indicates that some regions with severe iodine deficiency are still present. This research suggests that this program should be re-evaluated for remote areas with self-contained economic systems, and should be expanded and more effectively applied nation-wide.