PURPOSE: To determine the mean liver CT numbers, and differences between liver and spleen, and liver and back muscle CT numbers in normal children, and to correlate the findings with sex and age. MATERIALS AND METHODS: One hundred and five normal children aged 2-14 years underwent pre-contrast CT scanning. Mean CT numbers of the liver, spleen, and back muscles were calculated, as well as the differences in CT numbers between the liver and spleen (liver-spleen CT numbers), and between the liver and back muscles (liver-back muscles CT numbers). The results were correlated with age and sex. RESULTS: For all children, mean liver, spleen, and back muscle, and liver-spleen and liver-back muscle CT numbers were 70.22+/-6.51 HU, 53.28+/-3.0 HU, 58.31+/-3.57 HU, 17.13+/-6.57 HU, and 11.88+/-5.94 HU, respectively. Mean liver CT numbers and the difference between liver and spleen CT numbers were high in children aged less than seven, bet mean spleen and back CT numbers, and the difference between liver and back muscle CT numbers were not different by age. By sex, all the CT numbers did not vary according to age. The sex of a subject did not affect the CT number. CONCLUSION: The children's mean liver CT number was 70.22+/-6.51 HU and the difference between liver and spleen CT numbers was 17.13+/-6.57 HU. Younger children had higher liver CT and liver-spleen CT numbers than older children. No CT numbers varied according to sex.