Last week, Baset not only set Abdel Baset al-Megrahi free but also allowed him to return to Libya on so-called compassionate grounds.
Megrahi, who is terminally ill with prostate cancer, was the only person convicted in the 1988 airline bombing that killed 270 people.
According to a Rasmussen Reports' survey, majorities across every demographic category strongly disagreed with the decision.
Just 10 percent agreed with the decision, Fox News reports.
Sixty-three percent of adults said they followed news reports about the Lockerbie bomber.
The survey comes after a host of top U.S. officials have condemned the decision.
Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, said in an interview Sunday he was "appalled" by the move.
FBI Director Robert Mueller sent a letter to Scotland's Justice Secretary Kenny MacAskill saying the release "gives comfort to terrorists" around the world.
The survey taken on Saturday, Aug 22 and Sunday, Aug 23 was based on interviews with 1,000 adults.