To assess the changes with MRI in the shape and volume of fetal kidneys during gestation and to establish a normative curve for kidney growth during gestation.A total of 142 human singleton fetuses without urogenital abnormalities between 20 and 36 weeks of gestational age (GA) underwent a prenatal MRI. T2-weighted images (Single Shot Turbo Spin Echo) were used to measure the following kidney variables: bipolar diameter, anteroposterior (AP) diameter and volume. All variables were correlated to gestational age and a comparison was performed between the values in left and right kidneys.Linear regression analysis showed a correlation of both bipolar and AP diameter, area and volume with GA in weeks (p<0.0001). The bipolar diameter increases twice as fast as the AP diameter with increasing GA. The bipolar diameter also expressed the least variability around the regression line. No substantial volume differences between left and right kidney could be identified, however, a significantly larger area and greater bipolar diameter (p<0.01) of the right kidney compared to the left kidney was found.This study proves that fetal kidney volumes increase linearly with increasing GA. The proffered normative curve can be used to detect volumetric abnormalities in pathologic cases and assess growth normalization after therapy. At the same time, the similar volumes, but significantly different areas and bipolar diameters of left and right kidneys, clearly demonstrate the different morphology of left and right kidneys in fetuses.