It is important to determine chorionicity and amnionicity in multiple pregnancy which is best performed during the first trimester. Monochorionic twins should be suspected when monochorionicty is diagnosed. Twin fetuses have growth charts of their own. Monochorionic twins may have unbalanced vascular connection like TTTS and TRAP sequence. There are certain pitfalls during biophysical assessment of multiple pregnancy that should be taken into consideration. There are special types of multiple pregnancy like conjoined twins, hetertopic pregnancy and complete hydatidiform mole with coexistent twin.