A Los Angeles Times/Bloomberg telephone poll of 1,312 registered voters taken between Friday and Tuesday found 42 percent of Democrats favored Clinton. Her nearest rival, Sen. Barack Obama, D-Ill., had 33 percent support, up from 21 percent in a similar survey in early December, the Times said.
Former Sen. John Edwards, D-N.C., had 11 percent support.
While McCain led among Republicans with 22 percent, his lead was nearly within the poll's 4 percentage point margin of error for two other GOP hopefuls. Former Arkansas Gov. Mike Huckabee had 18 percent and 17 percent favored former Massachusetts Gov. Mitt Romney.
Former Sen. Fred Thompson, R-Tenn., who ended his candidacy Tuesday, drew 10 percent, the poll said. Former New York Mayor Rudy Giuliani fell from first place with 23 percent in the December poll to fourth place with 12 percent support of likely Republican voters.