Purpose: The objective of this study was to standardize thyroid gland volume measured by ultrasonography in 0-16 age group ofchildren. Methods: Thyroid volumes of 302 healthy children (150 males, 152 females) in the age group of 0-16 years were measured. Transverse (x), sagittal (y), and anteroposterior (z) lengths ofright and left lobes and isthmus were measured and then their volumes were calculated with elipsoid formula ( V= (n/6).x.y.z). Volumes of two lobes and isthmus were added to each other in order to get thyroid gland volume. For statistical analysis Kruskal Wallis and student t tests were used. Results: The cases vere divided into six and eight groups in respect of age and height. Volumes of thyroid measured in age groups were: 1.8± 0.7 cm3 in 0-2 years, 2.9 ± 0.6 cm3 in 3-5 years, 3.6± 1.2 cm3 in 6-8 years, 4.8± 1.5 cm? in 9-11 years, 9.6 ± 5.7 cm3 in 12-14 years and 12.8 ±5.8 cm3 in 15-16 years. Volumes of thyroid measured in height groups were: 2.1 ± 0.8 in 99 cm and belov, 3.2 ± 0.9 in 100-109 cm, 3.4 ± 0.9 in 110-119 cm, 4.4 ± 0.8 in 120-129 cm, 4.6± 1.8 in 130-139 cm, 5.7± 1.6 in 140-149 cm, 10.4 ±5.7 in 150-159 cm, and 13.6 ± 6.6 cm3 in 160 cm and over. The differences between these groups were statistically signifıcant. Conclusion: Positive correlation vas found between age and height and thyroid gland volume. Thyroid volumes in groups of 12 years and over were signifıcantly different from the smaller age group. This difference was thought to depend on physical and endocrinological changes in adolescence.