For three generations, relatives of 23-year-old Rex Moers have attended Gallaudet University, learning to survive as deaf members of a hearing society.

But even as Gallaudet educated Moers and his parents and grandfather, it maintained a tradition that clashed with its message of equality and opportunity for the hearing impaired. In its 124-year history, Gallaudet has never had a deaf president.

Yesterday, Moers, wearing a yellow button emblazoned with the words "Deaf President Now," was among an estimated 1,500 people gathered here to demand an end to that legacy.

The demonstration, held under a brilliant sky on the university's campus of red brick buildings in Northeast Washington, was punctuated with cheers and chants and the fluttering of hundreds of hands in sign-language applause.

"I am at this rally because my grandfather graduated from Gallaudet in 1927 and my parents in 1955," said Moers, speaking through an interpreter, "and I feel a lot of spirit in supporting this rally for a deaf president."

The rally was attended by a broad cross-section of the deaf community -- students, faculty members, alumni and others -- and university officials said the campus demonstration was unprecedented in its size and scope.

"This is a historical event -- you could call this the first deaf civil rights activity," said Allen Sussman, one of about 20 deaf speakers to address the rally.

"And what it is all about," said Sussman, a professor of counseling and psychology, "is that we want a deaf president of Gallaudet."

As Sussman spoke, the crowd waved homemade placards saying, "I have a dream -- a deaf president" and "Are you a racist? Earist? Why not a deaf president?"

Gallaudet, which has 2,400 students and is the world's only university for the deaf, has been searching for a new president since Jerry C. Lee resigned in August to take a job with a furniture manufacturer.

Shortly before the rally began in the stands near the football field, the university announced that the search for a new president was narrowed to three finalists, including two deaf persons.

The finalists, who are scheduled to be interviewed by the university's board of trustees this weekend:

Harvey J. Corson, 43, superintendent of the Louisiana School for the Deaf in Baton Rouge for the last 11 years. Corson, a third-generation deaf person, has a bachelor's degree in economics and a master's in education from Gallaudet, a master's in administration and supervision from California State University and a doctorate in education from the University of Cincinnati.

I. King Jordan, 44, dean of Gallaudet's College of Arts and Sciences. Jordan has been part of Gallaudet for 15 years and has a bachelor's degree in psychology from Gallaudet. Jordan, who is deaf, also has a master's in arts and a doctorate in psychology, both from the University of Tennessee.

Elisabeth A. Zinser, vice chancellor at the University of North Carolina. Zinser said information about her age and academic degrees would have to be released by Gallaudet.

The board of trustees is expected to announce its choice Sunday evening.

Catherine W. Ingold, Gallaudet's chief academic officer and a member of the search committee, said that she personally has always wanted the university to have a deaf president. "It comes down to factoring that desire into the overall needs of the university," she said.

But members of the Deaf President Now Committee, which was organized about two weeks ago by students and professionals, contend that a deaf person should be chosen now rather than later to head the university because the position is considered the highest office in the world of deaf education.

The significance of having a deaf person in that position was underscored most dramatically by Jeff Rosen, a deaf lawyer who helped form the committee. Wearing a red T-shirt printed with the words, "Deaf Prexy Now," and standing in the back of a pickup truck so that his sign language could be seen by the crowd, Rosen declared:

"People died in the civil rights movement. They were jailed in protesting the Vietnam war. I stand here in 1988 asking, 'What do you believe in? What is your cause?' "

Rosen said that the rally was intended to tell university officials that "we won't wait" and that "we are going to take control over our future."