Introduction. The prediction of fetal birth weight is crucial for establishing a correct birth plan. The two main methods to predict the fetal size are: clinical estimation and ultrasound measurement. The clinical evaluation of fetal weight is based on abdominal palpat ion of fetus, determination of height, body mass or abdominal circumference of the mother. It is subjective and not standardized. This is why the ultrasound examination is thought to be more helpful and accurate. Aim of the study. To assess the precision of the ultrasound in the prediction of fetal birth weight. Materials and methods. This is a descriptive, non experimental study of pregnant women hospitalized during 2017 in the Obstetrical department of Municipal Hospital No 1 of the Republic of Moldova. The pregnant patients were admitted to the hospital because of the pregnancy complication. All the patients underwent ultrasound examination by the same experienced sonographer. The obtained fetal measurements were: biparital diame ter, head circumference, femur length, humerus length and Abdominal circumference by Gray scale two dimensional ultrasound. Birth weight was best estimated by three different formulas. Shepard formula: Log 10EFW 1,2508 (0,166 x BPD) (0,046 x CA) (0 ,002646 x CA x BPD). Formula Aoki: (1,25647 x BPD3) (3,50665 x FAA x LF) 6,3 Formula Hadlock: Log10EFW =1,3596 0,00386(CA x LF) 0,0064(CC) 0,00061 (BPD x CA) 0,0425 ( 0,174 ( In all formulas EFW stands for estimated fetal weight ( BPD biparietal diameter ( FAA fetal abdominal area (cm 2 LF femur length ( The newborns were weighted 2 hours after the delivery using a graduated scale and the actual birth weights were recorded. The data collection was made by extraction of the important information from medical files of the hospitalized patients, in accordance with the elaborated questionnaire for this research. Statistical processing was performed using the program Microsoft Office Excel. Results. The total number of par ticipants comprised 200 pregnant. From these, 100 at term and 100 who delivered prematurely. The average age of mothers of children was 29.07 years, the age ranged from 21 to 42 years. The average weight of neonates at birth was 2057 gr. The difference bet ween the estimated fetal weight by ultrasound and the birth weight of the fetus varied between 10 and 520 grams. The deviation from real birth weight in three formulas corresponded to: Shepard 334g, Aoki 366, Hadlock 289g. The average difference was 355.71 grams. The difference <300 grams was 47.62%, 300 grams was 52.38%. Conclusions. The ultrasound evaluation showed to have an average sensitivity in the predicting the fetal weight at birth ( From the formulas used, the Hadlock formula shows less deviation from neonatal weight.