Introduction:Ultrasonography is being a painless, non–invasive, non–ionizing, portable, redoable and relatively inexpensive modality used to evaluate fetal growth parameter many times during pregnancy. Aim : To assess relationship between sonographic gestational age and fetal FL and FL/FOOT LENGTH between 16 and 39 weeks of gestation and to compare its accuracy with other biometric parameters. Materials and Methods: Prospective cross sectional study was performed on 500 normal singleton pregnancies at second and third trimesters between 16–39 weeks. The study was conducted on a gray scale real–time ultrasound scanner using linear and sector transducers to measure the standard fetal biometrics and fetal fetal FL and FL/FOOT LENGTH at our department of radiology , PES institute of medical sciences whic is a rural medical college adjoining three states (Andhra Pradesh , Karnataka and Tamilnadu). Results: Biparietal diameter (BPD), Head circumference (HC), Abdominal circumference (AC), and Femur length (FL) and Fetal FL and FL/FOOT LENGTH were compared with standard charts and scatter graphs were plotted. Coefficient of correlation were calculated which were 0.9620, 0.8632, , 0.9853, 0.8648 for BPD, HC, AC, FL and FL/FOOT LENGTH respectively, proving them reliable indicators . FL measured in the present study was compared with standard nomogram. A statistically significant curvilinear correlation was found between the FL and GA indicating it to be a reliable indicator of GA. Significant coefficient of correlation (0. 0.920 4) was observed between FL and GA indicating it to be a reliable parameter. Conclusion: The HL was most accurate parameter next to FL in assessing GA. The study also indicates that combination of BPD, HC, AC, FL, FL is more accurate in predicting GA than any single parameter, particularly in the third trimester of pregnancy.