The agency declined to release the juvenile's name, age or residence.
The Facebook posting, put up on Saturday but since removed, posed a quiz to readers, "Should Obama be killed?" The options were no, may be, yes, and "yes, if he cuts my health care."
Secret Service agents -- who investigate all potential threats against presidents -- spoke with the child and parents, and determined that there was no intent to harm Obama, agency spokesman Ed Donovan said.
The poll was not created by Facebook, but by an independent person using an add-on application that had been suspended from the site, Facebook spokesman Barry Schnitt said earlier this week.