Heitkamp is viewed favorably by 46 percent of likely voters, while 35 percent have an unfavorable view of her. Berg's numbers are a bit worse, with 42 percent seeing him favorably and 37 percent viewing him unfavorably. Both candidates have been attacking each other over the airwaves (with plenty of help from outside groups in the inexpensive state).
There's a gender gap on both sides -- Heitkamp has the support of 51 percent of women and 42 percent of men, while Berg garners support from 51 percent of men and 44 percent of women. Heitkamp edges Berg in independent support, with 48 percent to his 43 percent.
While the Senate race may be tied, the poll shows Republicans dominating the White House race and the contest for the state's at-large House seat.
Heitkamp will need to significantly outrun the president to win the Senate race: 40 percent support President Obama while 54 percent back Mitt Romney.
And in the race for Berg's open House seat, Democrat Pam Gulleson lags behind Republican Kevin Cramer. He has 49 percent support to her 37 percent, with 12 percent of voters still undecided.
The poll was conducted Oct. 3-5, surveying 625 likely voters. The margin of error is plus-or-minus 4 percentage points.