Luxembourg overwhelmingly rejected in a referendum on Sunday giving full voting rights to foreign nationals, who make up nearly half the population.
More than 78 percent of voters in the European Union country said "No" to granting foreigners the vote, according to final results.
Had the vote been carried, the landlocked nation of more than half a million people would have been the first in the EU to grant foreign-born residents the right to vote in all the country's elections.
On her way out of a polling station in the capital, 55-year-old Nicole said she voted "No" because she believed the voting question should be solved by giving more foreigners Luxembourg citizenship.
"I think people should become Luxembourgers," Nicole, a municipal worker married to a Frenchman, told the AFP news agency.
Another voter, a civil servant named Claude, disagreed, saying: "We must enlarge the constituency and put an end to the political apartheid against foreigners."
Prime Minister Xavier Bettel had billed the referendum as a chance to boost the democratic credentials of the wealthy duchy, which is nestled between Belgium, France and Germany.
But as it became clear voters disagreed with his arguments, he admitted defeat.
"The message in clear and has been understood. This is not a success for the governing parties," said Bettel. "We will respect the result."
While campaigning on Saturday in the capital, also called Luxembourg, the prime minister said a "Yes" vote was also a vote for democracy and diversity.
"There is no other European country where only 40 percent of the population elects its representatives," Bettel said ahead of the referendum, in which 244,382 people were eligible to vote.
About 46 percent of the total population of 565,000 people are foreigners.
"No other country in the world, apart from Dubai, has our level of democratic deficit," he added.
Bettel's Democratic Party, which is in coalition with the Socialists and Greens, had proposed to enfranchise foreigners resident in Luxembourg for more than 10 years.
Around 35,000 mostly European migrants met the criteria.
After the Portuguese, who account for 16.4 percent of the population, the Grand Duchy is made up of French nationals (seven percent), Italians (3.5 percent), Belgians (3.3 percent) and Germans (2.3 percent).
Non-European foreigners - such as Cape Verdians, North Americans and Chinese - account for seven percent of the population.