The absence of bilateral renal pelvis separation is usually one of the findings reported on fetal ultrasound, which is normal and does not require special intervention. If the fetus has bilateral renal pelvis separation, this is an abnormal manifestation, and the treatment decision should be made according to the severity of the separation and the thickness of the renal cortex. If the separation is mild and less than 1cm, usually no treatment is needed and follow-up observation is sufficient. If the separation is more than 1cm, the thickness of the renal cortex should be observed. Thick renal cortex can be followed and observed, while thin renal cortex requires early termination of pregnancy. It is important to see a pediatrician promptly after delivery of the fetus to exclude urinary conditions, which often require surgical correction if they are due to fetal urinary malformations.