STORY: Lopez Obrador told reporters at a regular news conference that Foreign Minister Marcelo Ebrard would attend the summit in his place, as he had previously indicated.
The Biden administration has opted to exclude the governments of Cuba, Venezuela, and Nicaragua from the summit on the grounds of human rights and democratic shortcomings, a White House official announced.
Lopez Obrador was one of several leaders who threatened to stay away if not all countries were invited.
The Mexican president said policies of "exclusion" that had been imposed "for centuries" needed to change, criticizing what he called an unjustified desire for "domination".
He rounded on U.S. critics of Cuba, but did say he would visit Biden in Washington next month.