Background: Knowledge of the normal range of spleen size in the population being examined is very important because there are many different pathological conditions that may alter in spleen size. Also, gender, height, weight and BMI of individual, affect the splenic length and could result in incorrect interpretation of splenic measurements, spleen to left kidney ratio is one of recent parameter mention in literature aid in diagnosis of splenomegaly in children.Methods: The study was a cross-sectional study conducted in Khartoum state at Al-Buluk and Gaafar Ibnauf Paediatric Tertiary Hospital during the period from March 2018 to August 2018. A total of 101 children (males and females) with aged ranged 1 month to 5 years included in study. A transabdominal scan was performed, and measurement of spleen and left kidney taken after an ethical verbal consent from their parents, then data analyzed by SPSS, Mean±SD. Deviation for study variables calculated then correlation between patients factors and ultrasound measurements done.Results: The study found that the mean measurements of the normal size of the spleen and spleen to left kidney ratio for children up to five years of age, Splenic length was 7.24±1.12 cm, width was 3.83±0.81 cm , thickness 2.91±0.55 cm and spleen to left kidney ratio was 1.04±0.0.70 ranged (0.86-1.23). The male have larger spleen than female with no statistically significant differences in spleen sizes between the sexes. There was a strong significant correlation between age, weight, height spleen and left kidney length (p