OKLAHOMA CITY - Republican U.S. Senate candidates Jim Inhofe and James Lankford each have large leads over their Democrat challengers, according to the latest News 9/News On 6 poll.

The survey of 400 likely voters shows Inhofe, who is running for his fifth term, has the lead with 56 percent. Democrat challenger Matt Silverstein is behind at 32 percent, a gain of four points since last month's poll. Nearly seven percent of voters are still undecided.

In the race to fill Sen. Tom Coburn's unexpired term, James Lankford leads with 56 percent. Democrat challenger Connie Johnson trails with 28 percent. Twelve percent of voters are undecided in that race, according to the poll.

The general election is November 4th.

The survey of 400 likely voters was conducted Sept. 27-29 by SoonerPoll.com and has a margin of error of +/- 4.9 percentage points. Results are weighted by age and Congressional district, stratified to Oklahoma likely voter demographics.