The New York senator also outpaces her Illinois counterpart among black and Hispanic Democrats, according to a combined sample of two months of polls.
Neither Obama nor former North Carolina Senator John Edwards have threatened Clinton in national polls. But both are giving her a chase in other areas. Obama leads her in fund-raising for the primary and Edwards is running stronger in Iowa.
Nationally, the combined sample found that Clinton has the edge among black Democrats, with 46 percent of their support to Obama's 33 percent.
Her advantage is even wider among Hispanics. She has the support of 45 percent of them to Obama's 17 percent.