Images of graceful girls in national charming long dress have been a symbol of Vietnam. However, looking back the historic development of national dress, Vietnam not only has ao dai but also ao yem – the indispensable dress of ancient girls. In the old days, ao yem was called yem. It is an age-old dress which is maintained until today. Ao yem was used by all levels of society from working class to upper class. It also was used widely in traditional festivals therefore it was the national traditional clothes of ancient ladies. Ao yem appeared in Vietnamese life in a very old day but until Ly dynasty it was basically in shaped.Through the stream of history, ao yem was changing incessantly and improving its design. However the revolutions of ao yem only happended at the beginning of the last century while western trouser and skirt were entering Vietnam. In 17 century, ao yem did not have any big change of model. In 19 century, ao yem has a square piece is cloth with one corner cut away to fit under the woman’s throat. This scrap of fabric is secured across the chest and stomach with thin strings. There were three common models of ao yem: ao yem co xay, ao yem co xe, ao yem co canh nhan. Entering 20 century, ao yem was used widespread with many of rich designs and models. Ao yem which has brown color and was weaved by rude cloth was for labor. Urban women favored white, pink or red ones, while women in the countryside wore ao yem in brown or beige, colors suited to their rustic environment. On special occasions, like the Lunar New Year or festivals, rural women would also wear brightly colored ao yem. There is one kind of ao yem which was often wore by ancient ladies was called “yem deo bua”. The name was “yem deo bua” because it has a small pocket of musk beside and it was an advantage weapon of ancient ladies…furthermore, ao yem made many original love stories. In the old day when a girl had a date with her darling, she usually put a piece of betel inside her ao yem; it was called “khau trau dai yem” and maybe there is no kind of betel more supernatural than this kind of betel. Today, the ao yem is appreciated for its cultural and artistic values. And on festive occasions, women throughout Vietnam are embracing the ao yem and other traditional clothes with renewed enthusiasm.