Ultrasound is a safe, non-invasive technique that provides a more precise and objective method of determining thyroid volume than inspection and palpation, particularly in areas of mild endemicity, and generally whenever goiters are small. Thyroid volume is also correlated with age, weight, height and body surface area (BSA) in non-iodine-deficient areas. Different authors prefer different parameters to assess thyroid gland volumes. In this study, thyroid volumes were determined using ultrasound in 605 school children aged 6-11 yr who had been living for at least 5 years in Antalya. The correlation between age, BSA, height, weight, BMI and thyroid volume was sought in this mild to moderate iodine-deficient area. Somatic development of our children was in the normal range. Thyroid volume was significantly correlated with age (r=0.41, p<0.001), height (r=0.33, p<0.001), weight (r=0.30, p<0.001), BSA (r=0.33, p<0.001), and BMI (r=0.13, p<0.001). The most significant correlation was found to be with age. The application of the International Council for Control of Iodine Deficiency Disorders (ICCIDD) and the World Health Organization (WHO) thyroid volume references to our subjects resulted in prevalence estimates of enlarged thyroid of 31% based on BSA and of 34% based on age. In conclusion, when thyroid volumes are to be compared with reference values, assessment of thyroid volumes based on age is the most reliable method, in the event of normal somatic development. (J. Endocrinol. Invest. 24: 559-563, 2001) (C) 2001, Editrice Kurtis.