Her death was announced by the March for Life Education and Defense Fund, an anti-abortion group that she founded in 1974 and ran from her home. She was its president at her death. A board member of the group, Gene Ruane, said Wednesday that the cause had not been determined.

Ms. Gray, a lawyer in the Labor Department, was galvanized by Roe v. Wade, the 1973 Supreme Court decision that established a woman's right to abortion. She retired from her legal career and devoted the rest of her life to overturning that decision.

"It was such a shock to think that anyone would kill an innocent human being," she told a television interviewer. To allow abortion, she said, was out of character for a nation that had recently passed civil rights laws and had helped at the Nuremberg trials to convict Nazis of crimes against humanity.

A Roman Catholic, Ms. Gray believed that life began at fertilization, and that abortion was murder and not acceptable for any reason: not for rape or incest, for severe abnormalities in the fetus or to save the woman's life.

She joined forces with other abortion opponents, and together they devised a plan for a march in Washington. The first march took place at the Capitol on Jan. 22, 1974, the anniversary of Roe v. Wade. The March for Life group was formed later that year, with the purpose of overturning the ruling. Year after year, tens of thousands braved the cold, and sometimes snow or rain, to participate in the march.

Ms. Gray, slight, animated and articulate, with thick, curly hair and traces of her Texas roots in her speech, would rally the crowds by denouncing "feminist abortionists," comparing abortion to the Holocaust and crying, "Save the babies!" In recent years she invited women who felt they had been harmed by abortion to participate in the marches and to hold up signs saying they regretted their abortions.

She bent for no one. In 1979, when Eleanor Smeal, president of the National Organization for Women, suggested that groups for and against legal abortion should meet and try to find common ground, like promoting birth control, Ms. Gray refused, saying, "Pro-life people will not negotiate with baby killers."

After the 1981 march, attended by 60,000 people, President Ronald Reagan agreed to receive an anti-abortion delegation at the White House. But Ms. Gray refused to attend, saying she thought the president should have addressed the rally.

In 1987 she rescinded an award that her group had given to Dr. C. Everett Koop, the surgeon general, because she disapproved of his explicit talk about sex and his advocating the use of condoms to prevent the spread of AIDS. Ms. Gray believed that recommending birth control encouraged teenagers to have sex and made them "fodder for the abortion mills," as she put it.

"She really stuck to her beliefs and didn't care what people thought," said Jeanne Monahan, who is the interim president of March for Life's board of directors and a director at the Family Research Council, a conservative Christian group. "And yet she had a real graciousness about her as well."

Ms. Gray was born in Big Spring, Tex., on June 24, 1924. Her father was an auto mechanic, and she told The New York Times in 1981 that her childhood had been "economically debilitated."

After high school, she worked as a secretary for a year to raise money for college, then enrolled at Texas State College for Women in 1941. After the Japanese attacked Pearl Harbor that year, she joined the Women's Army Corps. She finished college after the war under the G.I. Bill, earning a bachelor's degree in business administration and a master's in economics. She received a law degree in 1959 from Georgetown University, which she attended at night.

No immediate family members survive.

Ms. Gray was active in her organization until the end. The Rev. Frank Pavone, the national director of Priests for Life, posted on the organization's Web site an e-mail message that he said she had sent him just days ago. It read in part, "We shall unify and stop the evil of abortion because it is evil."