The reform, which has been given a fast track through parliament, was adopted with 57 yes votes against three no votes. It also means that the president's term of office is extended from five years to six years.
Member of parliament Ana Figueroa, who belongs to the same party as Bukele, was the one who presented the proposal for the changes to the constitution. She argued that members of parliament and mayors can already stand for re-election as many times as they want.
The only exception until now has been the presidency, she said in a speech in parliament.
Marcela Villatoro, from the conservative party Arena and one of the three who voted against, said on her part that the proposal means that "democracy in El Salvador has died”.
You do not understand what indefinite re-election means: It entails an accumulation of power and weakens democracy, she said.
Nayib Bukele, who has called himself "the world's coolest dictator", has become popular through tough measures against gang crime and the violence that has characterized the country. But Bukele and his government have also been criticized for many innocent people being deprived of their freedom, including minors, as the government has implemented its tough policy against crime.