"I decided to shorten my mandate to allow presidential elections to be held on May 6. I will be a candidate," RTS state television quoted Tadic as saying on Wednesday.
The Serbian President is set to tender his resignation on Thursday. After that, Slavica Djukic Dejanovic, the speaker of parliament, will become the acting president until a new head of state is elected.
Serbia last month announced parliamentary and presidential elections for May 6.
Tadic’s move is regarded as a tactic to help his centre-left Democratic Party campaign that has been slipping in recent pre-election polls against Tomislav Nikolic's populist Serbian Progressive Party.
Tadic has also announced that he will contest for another term.
“I'm offering a road of European integration,” Tadic said, adding, “I will run in that election with optimism because of the positive trends in our country.”
Most surveys show the pro-Europe president would face his long-time rival Nikolic in a run-off.