Owens now leads Scozzafava by 33 percent to 29 percent, with Conservative Party candidate Doug Hoffman at 23 percent. Two weeks ago, Scozzafava led Owens by 35 percent to 28 percent, with Hoffman at 16 percent. The margin of error is 3.9 points.

Hoffman's support among Republicans has risen from 22 percent to 27 percent, while Scozzafava's has dropped from 47 percent to 40 percent.

"With just 10 points separating the three candidates, this is likely to be a very tight – and fiercely fought – campaign right through election day, now less than three weeks away," said Siena's Steven Greenberg.

Scozzafava is seen favorably by 37 percent and unfavorably by 33 percent, with 47 percent not knowing enough about her to voice an opinion. Owens is regarded favorably by 32 percent and unfavorably by 23 percent, with 64 percent having no opinion. Hoffman remains the most unknown with 71 percent having no opinion of him, while 23 percent see him favorably and 16 percent unfavorably.

On issues ranging from the economy to Afghanistan, Owens has a slight edge over the other candidates, but Hoffman has made the biggest gains in terms of which candidates voters think would do a better job.