"I'm just waiting and seeing what comes about, who files and what they do," Paul, a 75-year-old obstetrician who has run for president twice and made a Senate bid in 1984, said Wednesday.
Paul, considered the intellectual godfather of the Tea Party movement, has a nationwide donor network thanks to his 2008 run for the Republican presidential nomination, The Dallas Morning News reported.
His son, Rand Paul of Kentucky, was elected to the Senate last year on the strength of Tea Party backing, the newspaper said.
The 2012 Texas Senate contest began two weeks ago when Republican Sen. Kay Bailey Hutchison said she would not seek re-election.
Announced GOP candidates include Railroad Commissioner Elizabeth Ames Jones, Weatherford car dealer Roger Williams, and former Texas solicitor Ted Cruz, the Morning News said.
Lt. Gov. David Dewhurst has hinted strongly that he will run, the newspaper said.