The Venezuelan election commission has said the presidential election will be held on 14 April.
Acting President Nicolas Maduro had pushed for a quick election, hoping to benefit from an emotional outpouring at the death of Hugo Chavez.
Two recent polls have forecast that Mr Maduro would win comfortably.
Centrist opposition leader Henrique Capriles has confirmed that he will run against Mr Maduro.
Mr Maduro, a former bus driver and union leader who served as foreign minister and vice president under Mr Chavez, has vowed to keep Mr Chavez's self-styled socialist revolution alive.
He was sworn in as acting president in Congress yesterday and handed the red, yellow and blue presidential sash.
"I asked (the election authority) to comply with legal and constitutional obligations and immediately call elections," Mr Maduro told Congress as he cemented his position as heir-in-waiting.
The Supreme Court had earlier ruled that Mr Maduro did not need to step down in order to campaign, but the move was denounced by opponents as a violation of the constitution and a "fraud."
As Mr Maduro spoke in Congress, residents of some wealthy neighborhoods of Caracas banged pots and pans in a traditional form of protest.
Mr Maduro named Mr Chavez's son-in-law Jorge Arreaza as his vice president, and then returned to a military base where more than 2 million people have filed past the late president's remains to pay their last respects, and took his oath again in front of the casket.
Mr Chavez was a hero to millions of mostly poor supporters for using Venezuela's oil wealth to finance heavy social spending during his 14-year rule but he was seen as a dictator by his opponents.
He died on Tuesday at age 58 after a two-year battle with cancer.
Like Communist leaders Lenin, Stalin and Mao, his remains are to be embalmed and put on display "for eternity".
An eclectic cast of celebrities, leftist and center-right presidents and rogue leaders attended Mr Chavez's state funeral yesterday.
Iranian President Mahmoud Ahmadinejad, a close ally, broke with protocol to kiss the coffin, while Oscar-winning actor Sean Penn was also in attendance.