The poll will be a blow to Republicans in the state, who are hoping to field a challenger against Shaheen in 2014, when they believe they could have a chance without President Obama at the top of the ballot.
And it puts her in a much more comfortable position going into 2014 than a recent Republican poll, which indicated she has 49 percent support to a generic Republican candidate's 43 percent support.
Sen. Kelly AyotteKelly AyotteSenate rivals gear up for debates WATCH LIVE: Warren campaigns for Clinton in NH Green group endorses in key Senate races MORE (R-N.H.), elected in 2010, also sees high popularity, at 51 percent support.
But Shea-Porter's popularity has dipped since the election and she is now underwater, with 39 percent of those polled viewing her unfavorably and 38 percent viewing her favorably.
A number of New Hampshire Republicans privately mentioned Shea-Porter's district as a top target in the state in 2014, and this poll will serve to stoke that speculation. It's also the more Republican of the state's two congressional districts, and Obama won it by a little more than one percentage point in 2012.
Shea-Porter defeated former Rep. Frank Guinta in 2012, and he's considered a likely contender for one of the state's multiple races in 2014. He has not yet decided whether to run for his old seat or for Senate, but more polls like these could push him towards challenging Shea-Porter in 2014.
The survey was conducted among 581 New Hampshire adults statewide from Jan. 30-Feb. 5, and has a margin of error of plus or minus four percentage points. The portion concerning the first district was conducted among 256 residents of the district and has a margin of error of plus or minus 6.1 percentage points.
--This piece has been updated to reflect the margin of error in the first congressional district.