If both his parents were naturalized citizens at the time of his birth, yes he would be. Unfortunately I don't believe this is so, and hence he is not. He is not eligible to serve as president, nor vice-president. He is my senator, but unfortunately he can not run for president. I really like him.
Rubio’s parents were refugees from Cuba and WERE NOT U.S. Citizens at the time of their son’s birth ... Rubio explained this on a radio broadcast... in fact there is even dispute that they were even refugees - most likely illegal aliens ... but never the less ...