Brazil's health ministry confirmed on Friday a 38-year-old man died of yellow fever and said it was investigating eight other possible cases linked to disease.
Since December the ministry had received 12 reports of possible yellow fever in Brasilia, a spokesperson said.
"Three cases have been ruled out, one death has been confirmed and eight cases are undergoing laboratory analysis," the spokesperson said.
The last case of yellow fever in the country's capital was recorded eight years ago, according to the regional secretary of health, Jose Geraldo Maciel.
But Brazilian health authorities say there is no yellow fever epidemic.
"Urban yellow fever was eradicated in 1942. In the countryside there is a specific 'wild' yellow fever in certain regions like the Amazon," Health Minister Jose Gomes Temporao said two days ago.
The government launched a vaccination campaign in Brasilia and several other cities in the neighboring state of Goias after yellow fever was found in monkeys in public parks.
Yellow fever is an acute viral disease transmitted to humans by infected mosquitoes.