A survey of 597 voters who say they plan to participate in the Iowa Republican caucuses found Paul ahead in Iowa as Newt Gingrich's numbers declined for a second week, Public Policy Polling said.
Paul had 23 percent of the vote compared with 20 percent for Mitt Romney, 14 percent for Gingrich, 10 percent each for Rick Santorum, Michele Bachmann and Rick Perry; 4 percent for Jon Huntsman and 2 percent for Gary Johnson.
The North Carolina pollster, which describes itself as a Democratic polling company, said Gingrich's share of the vote has gone from 27 percent to 14 percent in two weeks. Public Policy Polling said negative ads have chipped away at Gingrich's image as a strong conservative.
Paul's support is strongest in voters younger than 45 and with voters who identify as either Democrats or independents but plan to participate in the Republican caucuses.
"Young people and non-Republicans are an unusual coalition to hang your hat on in Iowa, and it will be interesting to see if Paul can actually pull it off," the polling company said Monday in a release.
The poll, conducted Friday through Sunday, had a margin of error of 4 percentage points.