A mailing by Virginia Del. Gwendalyn F. Cody, a Fairfax County Republican facing a strong challenge in Tuesday's elections, has brought vehement protests from some of the people she quotes as praising her work in the legislature.

"It's a deliberate misrepresentation," said Donna Caudill, president of the Fairfax Education Association, a teacher group that supports Cody's Democratic opponent, Leslie Byrne.

"I emphatically disclaim that I . . . . have made any endorsement of the candidate," said Darrel L. Tillar, chairwoman of the Virginia Council on the Status of Women, a state agency that sent Cody and every other woman in the state legislature a letter of appreciation after the 1985 session.

The mailing quotes about 30 persons -- many of them prominent in politics and various government bodies -- as praising Cody or her stands on an array of issues that have come before the General Assembly. It was sent to Cody's constituents in the 38th House District in the Annandale area of Fairfax County.

Cody, who has served two terms in the legislature, lashed out at her critics. "If they sent me a letter and they did not mean it, then they are false people who are putting out false information and I feel sorry for them," she said.

Many of the statements quoted in Cody's mailing are taken from what several people said were form letters that were sent to a number of legislators and, some said, were not intended as endorsements.

Cody said the statements were not labeled as endorsements and were not solicited.

Byrne, her Democratic opponent, called the mailing "duplicitous" and a "pack of lies."

"I think anyone who sends Gwen a Christmas card ought to be careful that it's going to end up in her campaign literature," she said.

Not everyone quoted was upset. Mary E. Collier, a Republican and School Board chairman, said she supported Cody and called her a "strong supporter of public schools."