A Franklin & Marshall College poll released Wednesday shows the Republican supported by 47 percent of likely Pennsylvania voters to 32 percent for his Democratic rival, Allegheny County executive Dan Onorato. About a fifth of voters remain undecided with a week until next Tuesday's election.
A September poll by Franklin & Marshall showed Corbett with 36 percent to Onorato's 32 percent. A survey by a separate pollster last week showed the race tightening.
The men are vying for the governor's office now that term-limited Democrat Ed Rendell is finishing his maximum second term.
The poll of 489 Pennsylvanians deemed likely to vote was conducted during the week ending Sunday. The sampling error margin is plus or minus 4.4 percentage points.