If the 2016 presidential election were now, 43 percent of likely voters said they would choose Clinton, a Democrat, while 41 percent said they would opt for Chris Christie, New Jersey's Republican governor, results of the poll released Monday indicated.
Nine percent said they preferred another candidate and 8 percent said they were undecided, Rasmussen said.
Neither Clinton nor Christie, who was re-elected last week to another gubernatorial term, have indicated whether they'd seek their party's presidential nomination.
The survey's 3 percentage point margin of error put the preferences in a dead heat.
Not surprisingly, Clinton has the support of 77 percent of Democrats, while Christie had the backing of 73 percent of Republicans, results indicated. Among voters who said they weren't affiliated with either major party, Christie led Clinton, 42 percent to 33 percent.
Results are based on a nationwide survey of 1,000 likely voters conducted Thursday and Friday. The margin of error is 3 percentage points.