Nellie Gray, president of the March For Life Fund, which organized the rally, said her organization would look for more cases to present to the U.S. Supreme Court and try to get bills introduced in Congress to try to overturn Roe vs. Wade, the landmark legislation that 37 years ago legalized abortion.
"We will begin in 2010 to stop the killing," Gray told the audience.
She recalled President Barack Obama's comments when he visited the Buchenwald, Germany, death camp and said he couldn't forget the horror he saw.
"Mr. President, it seems that you have forgotten," she said to applause and hoots of approval.
She said whoever occupies the White House is "the president of all the people and that includes the innocent pre-born children."
Abortion-rights activists staged a counter-protest.
Cecile Richards, president of Planned Parenthood Federation of America, said in a statement on the organization's Web site, that deciding whether and when to be a parent is "one of the most personal and important choices we make."
"However, a woman's right to make personal healthcare decisions is under continuous assault by anti-choice organizations and individuals who use harassment and intimidation tactics in their attempt to deter women from seeking healthcare and doctors from providing it," she said in the statement.
Speeches by anti-abortion forces expanded beyond the abortion issue to include euthanasia because some people "have a disregard for life ... and won't respect" the elderly or people with disabilities, Gray said.
Speakers, including religious leaders and congressional members, spoke against abortion and against federal funding for the medical procedure.
Sen. Sam Brownback, R-Kan., who isn't seeking re-election, said he was "more confident than ever that we are going to win the cause of life."