Introduction: For the management of obstetric cases, it is very important to know the EDD. But in our set up most of the women do not know the date of LMP and hence it is difficult to predict the EDD. Therefore, ultrasound examination plays an important role in determining the EDD. Aims: To formulate the ideal length of fetal kidney to the corresponding gestational age and to study of echo pattern of fetal kidney and its correlation with pregnancy outcome. Materials and methods: 200 pregnant women with known LMP were taken for the study. Gestational age by LMP was calculated and it ranged from 20 weeks to 40 weeks. All the cases were subjected to ultrasound examination. Besides other information through USG, special emphasis was made to calculate USG gestational age by conventional method of measuring BPD. FL. AC. At the same time the renal length and renal medullary echo pattern was examined in all the cases. The cases were grouped according to the gestational age by LMP and mean renal length was calculated for each gestational age group.