When Lola McAdoo graduated in 1958 from Bennett College -- one of only two historically black women's colleges in the U.S. -- she did what most well-educated African-American women of the segregated South did. She taught school, for $2,400 a year.

But over the decades, as the soft-spoken Ms. McAdoo taught thousands of students in Greensboro, N.C., she differed in one key respect from most of her Bennett classmates and many other black professionals of her generation: Every year, without fail, Ms. McAdoo gave money to her alma mater, starting at $50 in 1959 and rising most recently to $2,000. This year, Ms. McAdoo, now 67 and retired, pledged to leave her house, worth about $100,000, to Bennett.

Long-term financial support from ordinary alumni has been rare at the nation's more than 100 historically black colleges and universities. Among black schools responding to an annual survey of college giving over the past decade, an average of only 5% to 10% of alumni made annual gifts, compared with an average of about 25% for all private schools. At some elite schools, as many as 60% of alumni give regularly.

Now, as historically black schools contend with flat or declining gifts from corporations and foundations, a less-than-affluent student body and, in some cases, poor management, they are trying to encourage habits like Ms. McAdoo's.

New fund-raising strategies are resulting in a surge in alumni giving. At Bennett, alumnae gifts more than doubled over the past year to $1.1 million. At Fisk University in Nashville, Tenn., the alumni office last year found correct addresses for more than 2,000 alumni it previously couldn't reach and now sends biweekly e-mail to alums; last year, alumni gave $1.4 million. Dillard University, a 2,400-student school in New Orleans, got more than $860,000 in alumni gifts last fiscal year, 10 times what it raised from graduates five years ago. "Dillard started late and has found that there is huge opportunity in alumni giving," says the school's president, Michael L. Lomax. "We have found this gold mine, and we're working it for all it is worth."

Many African-American graduates have given generously to historically black colleges. Others have donated to the United Negro College Fund, which since its founding in 1944 has raised $2 billion for a group of 39 historically black schools. Celebrities such as Oprah Winfrey and Bill Cosby have made large, well-publicized gifts.

Last month, Dallas radio host Tom Joyner gave $1 million through his foundation to students at Morris Brown College, a predominantly black school in Atlanta recently stripped of its accreditation for fiscal mismanagement. But star power can't substitute for the financial cushion schools get from an established pattern of alumni giving, say collegiate fund-raising experts.

One explanation for black schools' lower levels of alumni giving is the long-standing gap between the wealth of African-Americans and that of whites. Many black colleges had never asked alumni to donate "because they had corporation funding or they thought that black alumni were not yet at the point they could give," says Dr. Marybeth Gasman, who teaches at the University of Pennsylvania and co-wrote a recent study on fund-raising at historically black colleges.

Increasingly, many black schools find they must reach their alumni before another school does -- often a majority-white one. In 2001, nearly 80% of black professionals who received an advanced degree did so at a majority-white school.

One of the largest-ever alumni gifts to Harvard Law School was a $3 million donation in 1992 from Reginald Lewis, former chairman and chief executive of TLC Beatrice International Holdings Inc. Several black schools, including his undergraduate alma mater, Virginia State University, shared $1.4 million in unsolicited gifts from Mr. Lewis before his death in 1993. The reason for the larger gift to Harvard was simple, says Loida Nicolas Lewis, Mr. Lewis's widow. "Harvard knocked on the door 20 times, and Mr. Lewis eventually answered the door."

Most predominantly black schools were founded in the 19th century by white church denominations or wealthy families in the North to educate freed slaves in religion, farming or teaching. By the 1960s, an estimated 95% of black college students were attending historically black institutions. They were bedrocks of the black middle-class and civil-rights activity.

After desegregation, thousands of black students enrolled at previously all-white state universities. By 2001, only 18% of black college students were attending historically black schools, according to the National Center for Education Statistics. Black schools' students have grown increasingly poor: 75% to 90% of students at most of the schools get financial aid.

Meanwhile, the number of black households with incomes of $100,000 or more has grown rapidly, to 5.6 million in 2001 from 3.1 million in 1991, according to U.S. Census data. That growth prompted the Kresge Foundation of Troy, Mich., to award $18 million in 1999 to a group of five historically black schools, including Dillard and Xavier University, also of New Orleans, to help them pursue alumni with techniques such as monthly bank-account debits and advanced estate-planning.

Even the titans of historically black colleges are trying to boost alumni giving. Last year, Morehouse College in Atlanta received its largest-ever corporate gift, a $3 million pledge from Coca-Cola Co. But it also has raised more than $11 million from alumni in the past three years, including two gifts totaling $3 million.

"Philanthropy is a responsibility," says Robert Davidson, one of the recent big Morehouse contributors and the owner of a Los Angeles paint manufacturing company. "The success of historically black colleges will be determined by the willingness of our graduates to support them."