ULTRASOUND has revolutioned the care of women carring twins.First trimester evaluation is the best time to determine chorioniocity and amnioniocity in multiple gestations.First trimester diagnosis is based on the number of gestational sacs, amnions and yolk sacs.Growth rate in multiple multiple gestations during the fist and early second trimesters parallels the growth rate of singleton pregnancies, dropping off during the late second and third trimesters.Most cases of growth discrepancy are diagnosed at the second half of the pregnancy and twin to twin transfusion Syndrome is the main differentional diagnosis.ULTRASOUND is very important for evaluating complications of twin pregnancy some Complications are more frequent in twin than singleton gestations such as preterm delivery, IUGR, preeclampsia, PROM, Placenta previa, Abruptia placenta, post partom hemorrhage, umbilical and accidents and congenital anomalies and some are unique to twins: TTTS, twin emboliesation syndrome, Umbilical cord entanglement, Conjoined twin.