We aimed to compare the renal length determined by scintigraphy using Tc99m dimercaptosuccinic acid (DMSA) scan and ultrasonography in children. Sixy-seven kidneys of 37 consecutive children (6 male, 31 female; mean age: 6.4±4 yrs, range: 5 months-13 years) which showed normal renal Tc-99m DMSA were included in this study. Wilcoxon's matched paired test and Spearman's rang correlation test were usedfor comparison. A close correlation between the values obtained with these two methods was observed (r=0.95). There was also a good correlation between renal length, age, body weight, and height of the children. The correlation with these easily available parameters permits us to calculate expected renal length of d child and compared it with obtained values.