Apart from the ban, Messi was handed a US$50,000 fine.
After Argentina was last month denied two penalty claims in their 2-0 Copa America semi-final defeat, Messi stated that the championship was set to be won by Brazil.
He also added that he was disappointed with the judging and the organization of the championship and at the end refused to receive the third place medal after Argentina won against Chile.
"Sadly, the corruption, the referees, they don't allow people to enjoy football,’ said Messi after the match with Chile. CONMEBOL called the accusations "groundless" and "unacceptable."
The suspension will cause Messi to miss matches of his national team against Chile and Mexico in September and October, one against Germany and another adversary to be picked.
Messi is also suspended from the first match of the South America World Cup qualifiers next March because of a red card he received during the disputed game against Chile. It was his second red card in his career. He will be allowed to play for his country again in November.
CONMEBOL said Messi can appeal the decision but until now neither Messi nor Argentina’s soccer association have made comments about it.