The survey, taken Aug. 7-10, has a margin of error of plus or minus 4.7 percent, meaning Sanders’s lead is not considered statistically significant by pollsters.
Clinton has maintained a modest edge in other recent polls from the Granite State, including a WMUR Granite State poll last last month that had her up by 6 percentage points among likely Democratic primary voters.
Still, the latest survey reflects a surge by Sanders this summer that has turned the Democratic race into more of a contest than almost anyone expected.
Sanders, a self-described democratic socialist who has been drawing huge crowds around the country, is running strongest in New Hampshire, where he started the race better known because of his long representation of Vermont.
Clinton maintains leads of more than 25 percentage points in recent polls from Iowa, the nation’s first caucus state, while her lead nationally has average about 35 points, according to surveys tracked by Real Clear Politics.
In the new poll out of New Hampshire, Vice President Biden, who has not said whether he’s running, got 9 percent. The other announced Democrats in the race -- former Maryland governor Martin O’Malley, former Rhode Island governor and senator Lincoln Chafee and former Virginia senator Jim Webb -- received 1 percent or below.
Survey research analyst Scott Clement contributed to this report.