An echographic study of the fetal normal kidney in 274 fetuses (548 kidneys measured) from 15 to 40 weeks of pregnancy is proposed by the authors. This work includes morphologic and biometric study with the growth curves of 4 parameters. It is shown that both kidneys are morphologically similar and their growth is continuous and there is a constant ratio between the different parameters. Ratios are established: Length/BPD = 0,45 +/- 10%, Width/BPD = 0,27 +/- 10%, Thickness/BPD = 0,26 +/- 10% which are very useful for the echographist. One hopes that with morphologic and biometric criteria of normality, the early detection of urinary tract malformations will be easier.