Hutchison said during a radio interview she was prepared to resign her seat in October or November to pave the way for a special election for her successor, The Hill reported.
Hutchison said she couldn't be a senator and run the kind of gubernatorial campaign she wanted.
"I am trying to do everything that I can while I'm in office to responsibly serve as a senator, but it is hard because my heart is in Texas," Hutchison told WBAP, Arlington, Texas. "The actual leaving of the Senate will be sometime -- October, November, in that time frame."
Hutchison said she stepped back from a run for the governorship for fellow Republican Gov. Rick Perry, who assumed office in 2000 when George W. Bush resigned to become president and has twice won re-election.
"I just can't (stay in office) as long as Gov. Perry's in the race," she said. "No one expected him to run again."