Moore, a conservative who ran for office as "the Ten Commandments judge," said he was "disappointed" in the decision by a federal judge that said the monument violates the constitutional separation of church and state.
"I have no plans to remove the monument," Moore said at a news conference next to the monument. "We will lodge an immediate appeal."
Moore's lawyers said they would appeal the ruling to the 11th U.S. Circuit Court of Appeals.
Moore criticized U.S. District Judge Myron Thompson for using the word "religion" almost 150 times in the 94-page opinion he issued on Monday.
"If the court can't define the word religion, it has no business telling the state of Alabama or anybody else what they can and can't do with relation to God," Moore said.
Moore said it was hypocritical for Thompson to have ruled that the Ten Commandments monument "has the primary effect of endorsing religion," when Thompson's federal court building has a sculpture of the Greek goddess of justice.
"The court has said I don't know what religion is, but you've established it," said Moore's attorney, Stephen Melchior.
Moore and Melchior both contended that the ruling did not order the Ten Commandments monument to be moved out of the Alabama State Judicial Building.
"There is no order in existence at this time to remove the monument," Moore said. "If an order is issued regarding the movement of the monument, we'll take that up with a higher court."
While Judge Thompson did not order immediate removal of the monument, he said it was unconstitutional and that he "will allow Justice Moore 30 days to remove it."
"If the monument is not removed within 30 days, the court will then enter an injunction requiring Justice Moore to remove it within 15 days," Thompson said.
Thompson ruled that "while the chief justice is free to keep whatever religious beliefs he chooses, the state may not acknowledge the sovereignty of the Judeo-Christian God and attribute to that God our religious freedom."
"The Ten Commandments monument, viewed alone or in the context of its history, placement, and location, has the primary effect of endorsing religion," Thompson's written opinion said.
Attorneys for those who filed the lawsuit against the monument urged Moore to remove it in light of the federal judge's ruling.
"We ask Chief Justice Moore to remove the Ten Commandments monument from the judicial building and to stop imposing his personal religious views on the people of Alabama," said Richard Cohen, executive director of the Southern Poverty Law Center, representing plaintiff Stephen Glassroth.