Betancourt, a French-Colombian national abducted by leftist rebels during her 2002 presidential campaign and freed in a dramatic army intelligence operation on July 2, is Colombia's second most-liked politician.
The poll said her popularity was at 63 percent.
But Betancourt, who ran for president on an anti-corruption platform and has lately called for dialogue with the guerrillas, has not defined any plans to re-enter politics.
The Gallup Colombia poll of 1,000 residents of the country's four biggest cities was taken late last month and had a margin of error of 5 percentage points.
The U.S.-backed Uribe was re-elected in 2006 after Congress passed a constitutional amendment allowing him to run for a second term. He is leaving open the possibility of another change in the law to let him run again in 2010.
Many of Uribe's own supporters say a third term by the combative leader would threaten the democratic balance of power in Colombia.
He has assailed the courts, the press and the central bank for not going along with his popular policies aimed at bringing peace and prosperity to Colombia.
Uribe was widely praised at home and abroad for ordering state intelligence officers to pose as aid workers and dupe the rebels into handing over 15 high-profile hostages including Betancourt and three American defense contractors.
Hundreds of other kidnap victims remain in the hands of the Revolutionary Armed Forces of Colombia, or FARC.
Uribe had 85 percent popularity just after the rescue, according to Gallup. Other polls gave him even higher numbers.
The bespectacled president, whose father was killed in a 1983 FARC kidnapping attempt, has made crushing the 44-year-old insurgency the cornerstone of his government.
Should he not run in 2010, Defense Minister Juan Manuel Santos is the most likely candidate to try to carry on Uribe's security push. Gallup says Santos has 56 percent popularity.
