Harvard University has been exonerated of charges that it discriminated against Asian Americans in undergraduate admissions because it gave preference to recruited athletes and children of alumni, the Education Department announced yesterday.

The department's announcement followed a finding Monday that the University of California at Los Angeles (UCLA) had illegally preferred whites over Asians in admissions to its graduate mathematics department. It was the first time the federal government has made a finding of discrimination against Asian Americans in higher education.

The Office of Civil Rights is continuing investigations of charges of restrictive quotas on high-achieving Asian Americans in undergraduate admissions at UCLA and undergraduate, law school and optometry school admissions at the University of California at Berkeley.

The review of admissions to Harvard and Radcliffe from 1978 to 1988 found Asian Americans were admitted at a lower rate mainly because few were children of alumni or recruited athletes -- groups to which Harvard gives preference. The review took two years.

"While these preferences have an adverse effect on Asian Americans, we determined that they were longstanding and legitimate, and not a pretext for discrimination," said Michael L. Williams, assistant secretary for civil rights.

William Fitzsimmons, Harvard's dean of admissions and financial aid, said the proportion of Asian Americans in its freshman class has grown from 6 percent in 1979 to 20 percent this year.