PPP surveyed 521 likely Democratic primary voters on March 17. Obama was the choice of 44 percent of those surveyed, while Clinton was the favorite of 43 percent. 13 percent were undecided. The margin of error was plus or minus 4.3 percentage points.
Obama led by 4 percentage points in a similar poll by PPP two weeks ago.
"Some folks in the national media have been treating North Carolina as if winning it is a given for Barack Obama," said Dean Debnam, president of Public Policy Polling. "The reality is that the state is pretty close, and either candidate could emerge with a victory."
The poll found that Obama enjoys a lead among unaffiliated voters (53 percent to 35 percent for Clinton), men (47-41 percent) and black voters (72-19 percent).
Clinton leads among registered Democrats (44-43), among women (44-42 percent) and among white voters (56-30 percent).