Objective The aim of the study was to establish a nomogram for renal parenchymal thickness throughout pregnancy. Methods One-hundred and twenty-eight healthy women with singleton, well-dated, uncomplicated second- or thirdtrimester pregnancies were prospectively evaluated for renal parenchymal thickness on routine ultrasound scans. The renal parenchyma was measured in transverse and sagittal sections using predefined criteria. Results There were no differences in anterior or posterior parenchymal measurements in either plane by fetal sex. On sagittal-section analysis, no differences were noted between the right and left kidneys. A nomogram was established on the basis of the findings. The results showed constant linear growth of the fetal parenchyma during pregnancy. Conclusions The normal fetal parenchyma grows at a constant, linear rate throughout pregnancy. The nomogram formulated may serve as a basis of future studies of the correlation of parenchymal thickness with postnatal kidney function in fetuses with urinary tract anomalies.