Hillary's leads over her nearest Democratic rival has jumped to 19 points (40-21), from 11 last month (29-18).
Hillary's share of the Democratic primary vote ballooned to 40% from 29% last month.
Sixty percent of voters from either party say Hillary would be a good president if elected.
Among all those polled, Hillary leads John McCain by a 52-46 margin and Rudy Giuliani 49-48.
Hillary's favorable/unfavorable is now 58/40, her highest rating since becoming a senator (up from 53/42 in November).
"As other candidates are getting more and more attention, Hillary is getting more and more support," said Clinton chief strategist and pollster Mark Penn. "This poll confirms that Hillary not only can win but actually is today winning."
Today's poll comes on the heels of a Newsweek poll showing Hillary leading every Democratic and Republican contender she was matched up against, and a Fox News poll showing voters believe Hillary would be the toughest on terrorism of any presidential candidate from either party.