Umbilical artery velocimetry was performed in 33 twin gestations to evaluate the predictivity of the test (umbilical artery S/D difference between the pair > 0.4) in the screening of discordant fetal growth. Four out of 10 cases of discordant fetal growth were identified by the test and it was abnormal in 1 out of 23 concordant twins. The sensitivity was 40%, specificity 95%, positive predictive value 80% and negative predictive value of 79%. In spite of its low sensitivity the test can be useful in detecting discordant fetal growth in twin pregnancies.