The three brown bears - Bjorne, Bolli and Bompa - were killed because neither the Lycksele Zoo, nor any other wildlife park in Scandinavia could take them, Swedish officials said.
"There is no space for them. They have to be removed," the head of the Lycksele Zoo, Irene Sjoegren, told the Associated Press news agency.
Bjorne, Bolli and Bompa were heavily marketed after their birth in January, with local children encouraged to propose names for them in a contest.
The cubs are to be stuffed by a taxidermist and the meat is to be sold to a slaughterhouse.
Animal lovers angry
Animal rights activists criticised the decision, saying the zoo was treating animals like a commodity.
"The decision to kill the bears demonstrates the irresponsible and ruthless treatment of animals at zoos," said a spokeswomen for Animal Rights Sweden, Catharina Krongh.
She also said zoos should take adequate measures to control their animal populations, if they do not have enough space for offspring.
But the co-ordinator of a bear breeding programme in Scandinavia, Hans Ove Larsson, said it was virtually impossible task to perform.
"It is always difficult to predict how many of the bears will be born. There is nothing unusual about this," he said.
Mr Larsson also admitted there was no guarantee that something similar would not happen in the future.
"Absolutely not. That will happen again. And we are talking not only about bears, but other animals. That is unavoidable," he added.
Nowhere to go
Animal rights groups said one of the possible solutions in future might be to transfer animals to wildlife refuges in other countries.
But Swedish officials said sending animals abroad was not a good idea.
Mr Larsson said bear facilities in continental Europe, and especially Eastern Europe, were not adequate.
He also stressed that releasing the cubs into the wild was not an option, as it would have taken years of training to teach them how to survive on their own.
There are about 1,000 wild bears in Sweden, and hunters are allowed to kill about 50 a year to keep the population from growing too quickly.