According to officials, Amlo has won about 55 percent of the votes.

While 88 million people were eligible to exercise their voting rights, the turnout was around 53 million.

Apart from choosing the new President, the people also voted for 128 senators and 500 deputies in Congress. The fate of state and local officials were also decided during the vote.

Both his opponents have conceded defeat and congratulated him.

The conservative National Action Party's (PAN) Ricardo Anaya is slated to finish second, while, Institutional Revolutionary Party's (PRI) José Antonio Meade will take the third place.

Jose Antonio Meade (left) and Ricardo Anaya (right) have conceded defeat. Images: Twitter

"I recognise his triumph, I express my congratulations, and I wish him the greatest success for the good of Mexico," Anaya was quoted in the media as saying.

The ruling PRI, which enjoyed popularity in Mexican politics for over four decades, has fallen out of favour of late.

Meanwhile, US President Donald Trump congratulated the Mexican President elect following the latter's victory.

"Congratulations to Andres Manuel Lopez Obrador on becoming the next President of Mexico. I look very much forward to working with him. There is much to be done that will benefit both the United States and Mexico!" Trump tweeted.

However, the Mexican President-elect is a fierce critic of Donald Trump and his Mexico policy.

Lopez Obrador had unsuccessfully contested two previous elections.

During his campaign, he promised to tackle corruption, which has perpetually plagued Mexico. He also promised better wages and pensions, matters which the incumbent government failed to effectively deal with.

Image: twitter.com/lopezobrador_