During a visit to the Cristo Rey Jesuit High School in Chicago three years ago, B.J. Cassin was stunned to discover that the inner-city school was successfully harnessing the labor of its students to pay its bills.

Cassin is a California venture capitalist with a reputation for generosity. The Cristo Rey officials had invited him in hopes he might write a check for a gym and a cafeteria. But he had a much bigger idea. "The light bulb went on over my head," he said.

Within hours, Cassin decided to spend $22 million to spread the Cristo Rey model to other parts of the country. Three schools have since been established and six more are on the way in what experts call a significant step to revitalize Catholic education in some of the nation's poorest neighborhoods.

At the four Cristo Rey network high schools in Chicago, Los Angeles, Austin and Portland, Ore., students are required to earn about three-quarters of their $8,450 annual tuition by working five days a month in banks, law firms, advertising agencies, financial offices and other businesses needing clerical help. And every student is encouraged to think about college.

At a meeting in Los Angeles before the Cristo Rey school was established there, a California teenager asked one of the Chicago students, "Don't you think it's nuts that you are doing all this work and don't see any money out of it?"

The Chicago student answered, "Maybe I don't see any money, but I get an education."

Other Catholic school innovations are also blossoming, educators say. Two virtually identical middle school programs, the Nativity model and the San Miguel model, have lengthened the school day and intensified instruction for students in several dozen cities.

John Convey, provost of Catholic University and a national expert on Catholic schooling, said such schools are succeeding for the same reasons that Catholic schools have historically helped children in poor and immigrant neighborhoods. These schools have "clear goals and high expectations concerning student performance, attitudes and behaviors," he said, adding that they "aggressively socialize the students to the school's norms and expectations" and have "communal organizational structures that produce a caring and supportive environment."

The problem is how to pay for all that.

Cassin, 69, attended Keith Academy in Lowell, Mass., one of many once-thriving but now-defunct Catholic high schools. He said he has long wondered how to solve the financial problem that did them in: The schools could no longer find enough priests, nuns and other self-sacrificing professionals who would teach for almost no pay.

Schools based on the Nativity model, including Washington Jesuit Academy and Washington Middle School for Girls, have eased the financial pressure by staying very small. They never have more than 75 students, they rely on donations from organization and individuals, and they use volunteers to guide the two-hour homework sessions -- held at school four nights a week -- that are a key to their success, said John J. Podsiadlo, director of the Baltimore-based Nativity Educational Centers Network Inc.

Cassin had supported the Nativity schools but he wanted more, so he was attentive when Cristo Rey President John P. Foley and development officer Jeffrey Thielman told him about their Chicago school.

It began in 1996 as a shaky experiment. No one knew how Cristo Rey's mostly poor Latino students would do in high-pressure professional offices. "When we sent them out to work the first day," Foley said, "I felt like hiding behind my desk."

Some mistakes did happen. Antonio Corona, a senior at the Chicago Cristo Rey school, said that in his sophomore year, he delivered a gift fruit basket to the wrong person (the names were similar) and did not realize his error until the present had been gobbled up. But the wronged executive forgave him, and as has happened frequently with Cristo Rey students, Antonio's earnestness and willingness to learn won the day.

Edward B. Shealy, director of employee programs at the Katten Muchin Zavis Rosenman law firm in Chicago, said that 32 Cristo Rey students are working this year, receiving fine performance reviews. "Some of the reviews say they are slow, or shy, but 85 percent of the reviews are excellent," he said.

About 93 percent of Cristo Rey students are poor enough to qualify for federally subsidized lunches, similar to the percentage in the public schools of their Pilsen/Little Village neighborhood in southwest Chicago. But the dropout rate is 1 percent and the graduation rate 93 percent, compared with the 21 percent dropout rate and 59 percent graduation rate in nearby public high schools.

Cassin hired Thielman to be executive director of his new Cassin Educational Initiative Foundation, and they put the Cristo Rey show on the road. A fifth Cristo Rey school is scheduled to open in Denver in the fall, followed next year by schools in Cleveland; Tucson; Waukegan, Ill.; and Lawrence and North Cambridge, Mass.

A planned New York City school has been delayed because of a problem that network officials have encountered often: The existing Catholic schools are objecting that the new school might lure away their students.

Cristo Rey and Nativity models were both begun by Jesuits. The ancient, educationally oriented Catholic order says it is looking for more ways to help inner-city children. John Armstrong, secretary for secondary and pre-secondary education at the U.S. Jesuit Conference in Washington, said the focus is on students who without some help "would very likely not get into the Catholic school system and never get into the mainstream of business life and things like that."

Convey, at Catholic University, also praises the work of the Brothers of the Christian Schools, whose San Miguel schools have many low-income students, and the Faith in the City initiative, a consortium of Washington area schools devoted to helping low-income students.

To grow, all the new networks need more energy and money, educators say. "I believe the potential to spread is there," Convey said, "but it depends upon adequate financial support from the religious communities and benefactors like Cassin."

Kevin Comeaux, 14, took part in a work-study program at Verbum Dei Catholic, a Cristo Rey model high school in Los Angeles.