ntroduction: Ultrasonographic determination of foetal size to estimate the gestational age is very important in the present day obstetric practice as a significant proportion of pregnant women are unsure of their last menstrual period. Aims & objectives: This study is an attempt to measure various parameters of the foetus for the prediction of gestational age in the IInd and IIIrd trimester of pregnancy by USG. Place and Duration of Study: FH Medical College with effect from Aug 2015- March 2017. Materials and methods: This is an observational study. Healthy pregnant ladies with a single live foetus were selected for the study. 328 cases were selected and they were examined for BPD, HC, AC, FL by a single observer on a single machine. Results: All parameters were measured in 328 pregnant females from 18 years to 35 years age for BPD, HC, AC, FL. A significant positive correlation was observed between the gestational age and all the parameters. Conclusion: All our values were slightly more than those of other authors in the early weeks of gestation, but as pregnancy advanced our measurements were nearly the same as those of other authors.