The Party of the Democratic Revolution candidate said he asked Mexico's Federal Election Institute for the recount after the initial tabulation gave the victory to Enrique Pena Nieto, CNN reported.
Lopez Obrador, who appeared to be the runner-up, had said Monday the vote was "plagued by irregularities." He made similar claims after narrowly lost to Felipe Calderon in 2006.
The Federal Election Institute is to begin verifying individual poll results Wednesday.
Pena Nieto has said it is time to move forward and told CNN en Espanol he wanted to encourage a bipartisan approach to governing.
"We have to be constructive and put aside our differences, which are only for competitions and electoral contests," Pena Nieto said Monday.