The poll found 40 percent of older Republicans and core identifiers with the Republican Party currently favor Gingrich for the nomination. Mitt Romney is favored by 21 percent of Republicans over the age of 55 and 23 percent of those who strongly identify with the Republican Party.
Gallup said older Americans and partisan Democrats and Republicans are typically more likely to turn out in general elections than younger voters and independents.
Gingrich also leads Romney among voters 35 to 54 years of age, 33 percent to 21 percent. Romney, however, leads among young Republicans, ages 18 to 34, at 26 percent compared with 19 percent for Gingrich, Gallup said Thursday.
Overall, Gingrich led Romney 33 percent to 23 percent.
The results are based on interviews with 1,665 Republicans and Republican-leaning registered voters in Dec. 5-11 Gallup Daily tracking.
The margin of sampling error is plus or minus 3 percentage points.