Baros made 93 appearances for the Czechs, scoring 41 goals.
Czech captain Rosicky has had fitness troubles throughout the Euros and missed Thursday's game with injury.
A statement on fotbal.cz, the Czech Republic football federation's official site, confirmed Baros' decision. It read: "[Baros' retirement] had been speculated about for some time.
"The 30-year-old has been the subject of sharp criticism, culminating in the first Euro 2012 match against Russia. When Baros was substituted, some fans booed him."
The Czech football federation's website also confirmed Baros received "long applause" from his team-mates in the dressing room.
Rosicky, meanwhile, has 87 international caps but, at 31, he accepts he is nearing the end of his career with the Czech Republic.
"I would love to continue, but on the other hand I'm not the youngest anymore and have had problems with my fitness," he told Arsenal's official website.
"I will take time to think about it. As I say, I would love to continue but I'm not stupid - I know I'm getting older and have to think about what is good for me."