(CNN) - Sen. Mel Martinez, R-Florida, announced Tuesday will not seek reelection in 2010.
In a Florida press conference, Martinez said his decision was not based on the likelihood he would face a tough reelection fight.
"I've faced much tougher obstacles in my life," he said. "My decision is not based on re-election prospects, but on what on what I want to do with the next eight years of my life."
The first term senator and onetime National Republican Committee chairman narrowly won his first Senate race in 2004. Martinez also served as Secretary of Housing and Urban Development during President Bush's term.
One congressional source cited Martinez's age, 62, and said "he is ready for the next chapter in his life."
It currently appears 19 GOP seats will be up for grabs in 2010.