INTRODUCTIONThe commonest problem an obstetrician faces frequently is the assessment of fetal maturity for either prolonging the pregnancy or terminating it, for complications such as fetal distress, pregnancy induced hypertension, diabetes and Rh incompatibility diseases. The means that are widely accepted for estimating fetal maturity are Gestational age, weight of the fetus. The methods used to estimate gestational age (GA) and predict the expected date of delivery are menstrual history, clinical examination, perception of fetal movement and Nagele's rule.1 Nagele's rule is in women with regular cycles and certain LMP, the EDD is calculated by adding 7 days to the first day of the LMP and then adding 9 months. A menstrual history could be misleading for a number of reasons, such as, many women do not accurately recall the first day of last menstrual period, particularly if they are not trying to conceive. LMP may be unreliable or misleading because of oligomenorrhea, abnormal bleeding events, use of oral contraceptives and becoming pregnant in the first ovulatory cycle after a recent ABSTRACT Background: Assessment of accurate gestational age of fetus is very imperative for proper obstetric management of normal as well as IUGR pregnancies. The objective of this study was to evaluate the accuracy of transverse cerebellar diameter as against the conventional parameters of Biparietal diameter, head circumference, abdominal circumference and femur length in normal pregnant mothers between 15 to 40 weeks and in antenatal diagnosis of intrauterine growth retardation. Methods: Study done on 100 women attending antenatal department, 80 were normal pregnancy cases and 20 were clinically suspected IUGR cases. In each patient BPD, HC, AC, FL and TCD was measured. Correlation of TCD was done with other measured parameters as well as with estimated gestational age of fetus. Results: There was no statistically significant difference between the age and parity distributions of two groups It was seen that 18 cases were below the fifth percentile for AC and HC, 19 cases were below the fifth percentile for BPD and 16 cases were below the fifth percentile for FL. In 16 out of 20 cases the TCD values were within the normal range. Only in 4 cases the TCD values were below the 5 th percentile. This difference in number of cases below the 5