Republican Sen. Ted Cruz of Texas has been mentioned as a possible presidential candidate in the 2016 election.
To run for president, the Constitution says a candidate must be a "natural born" U.S. citizen.
The Dallas Morning News reported Cruz holds dual U.S. and Canadian citizenship.
The Constitution doesn't mention dual citizenship.
Amid concerns that being born in Canada could derail a possible presidential bid, Cruz released his birth certificate to the paper.
It shows Cruz was born in Calgary, Alberta, on Dec. 22, 1970. His mother was born in the U.S. and his father was a native of Cuba.
In a statement released Monday night, Cruz says, "Because my mother was a U.S. citizen, born in Delaware, I was a U.S. citizen by birth. When I was a kid, my Mom told me that I could choose to claim Canadian citizenship if I wanted. I got my U.S. passport in high school."
In the statement, Cruz, a Tea Party favorite, announced plans that he would renounce his Canadian citizenship.
President Barack Obama in 2011 released a copy of his birth certificate confirming his birth in Hawaii. He was born to an American mother and Kenyan father, and faced sharp criticism from some conservatives who claimed he wasn't an American citizen.