Mesic received a Croatian Football Federation (HNS) delegation which informed him of preparations by the two countries to jointly stage the tournament.
The president said he supported the project because "organising the event with Hungary, a European Union member, would open many paths to the integration we aspire to".
HNS president Vlatko Markovic said he expected the Croatian parliament to endorse the Euro 2012 project this week, like the Hungarian parliament did yesterday.