Appropriate knowledge of gestational age is very essential for management of pregnancy particularly for determination of viability in preterm labour interpretation of biochemical serum screening test or for counseling patients regarding the option of pregnancy termination. Various ultrasonic fetal parameter like gestational sac mean diameter crown- rump length (CRL) biparietal diameter (BPD) Head circumference (HC) abdominal circumference(AC) and femur length(FL) are used for determination of gestational age. This study is being undertaken to find out other ultrasonic fetal parameter like fetal foot length (FTL) for determination of gestational age more accurately. In this study ultrasonic measurement of fetal foot length was done in 500 antenatal cases from 20 to 40 weeks of gestation calculated from the first day of last menstrual period. In this study we found that there is linear increase in the fetal foot length with increase in the gestational age and the correlation is significant with r value of 0.97. From our study we can conclude that fetal foot length is a reliable ultrasonic parameter for assessment of gestational age. Keywords: fetal foot length gestational age ultrasonic fetal parameter.