Weighing only 40 grams, the miniature monkey has no tail and is only five centimetres long, but already has a little moustache, just like its parents.
Both males and females of the species have long, white, Kaiser Franz Joseph-style moustaches.
Last year a young male was born to the parents. He's now lovingly taking care of his new sibling.
Zoo workers have not yet been able to determine the sex of the month-old baby, as it is always clinging to its brother or father's back.
"Mostly the father or elder brother piggybacks the baby around," said zoo director Dagmar Schratter. "Only when it starts to scream do they take it to the mother to suckle."
Emperor Tamarins are a threatened species, found in the rapidly disappearing tropical rainforests of South America.
Belonging to the marmoset family, the tamarin has claws on its fingers and toes which allow the animals to climb along vertical stems and even hang upside down to look for food.
Tamarins are bred in Schönbrunn and other zoos as part of a European Endangered Species Program.