Norway & Sweden flag up Euro 2016 interest
"We are cooperating really well and have done extensive preparation work," the countries' football associations said in a joint statement.
They said UEFA's final application criteria would be announced in April with a bidding deadline in February 2010.
Sweden and Norway said that if they got to hold Euro 2016, they would divide the matches roughly equally between themselves but had not chosen host cities.
Both nations have made plans to build new national arenas and need several bigger stadiums to host a European championship with 24 countries.
"Stadium capacity is the first priority," Karen Espelund, secretary-general of Norway's Football Association, told a news conference.