California atheist Michael Newdow had asked the justices to consider overturning their June ruling. The court ruled then that he could not legally represent his 10-year-old daughter in the case because he does not have full custody of the girl. The court declined without comment.
Newdow wants the words "under God" removed from the pledge.
He told justices in a filing last month that he had spent six years to keep his daughter from being told at school "that her father's religious beliefs are wrong, unworthy and inferior." Newdow said his custody fight with the girl's mother should not affect his right to pursue the case.
Because the Supreme Court settled Newdow's case without addressing the broader question of separation of church and state, other parents could pursue similar cases or Newdow could renew his lawsuit if he is awarded full custody.
Justice Antonin Scalia did not take part in Monday's court action. He had removed himself from the case earlier after making off-the-bench remarks indicating he believes the pledge is constitutional.
The case is Elk Grove Unified School District v. Newdow, 02-1624.