Iodine deficiency (ID) remains a significant global public health problem. The iodine status of rural areas of Kayseri Province, Central Anatolia was previously evaluated but a screening survey covering both rural and urban populations had not been conducted. The aims of this study were: a) to determine the nutritional iodine status by calculating urinary iodine excretion (UIE) of the school-children living in the districts, city centre and villages of Kayseri Province; b) to implement preventive measures. The study group was made up of 1,784 school-children (920, 51.6% females; 864, 48.4% males), aged between 7 and 12 yr. Height and weight of children were measured and urine samples were collected. The median UIE of all school-children was 25.5 +/- 17.2 mu g/l. Iodine status of the population was gauged based on median urinary iodine values categorised as normal (>= 100 mu g/l), mild (50-99 mu g/l), moderate (20-49 mu g/l) and severe (<20 mu g/l) ID and classified according to age, gender and body mass index (BMI). While UIE of 289 school-children (16.2%) was in normal range (>= 100 mu g/l), 747 of school-children (41.9%) had UIE <20 mu g/l. Although there was no significant difference in UIE of female children based on their BMI (p>0.05), in overweight and obese male children UIE was significantly higher than in normal or underweight children (p<0.001). In Kayseri, moderate and almost severe ID affects public health from intrauterine to advanced stages of life. This is due to geographical characteristics of this area causing insufficient amounts of iodine in the drinking water and traditional nutritional habits of the families. The local "Iodine Monitoring Committee" developed an action plan including information/education/communication activities to sustain monitoring so as to increase the inclusion of iodized salt in the region.