When the Roman Catholic Diocese of Brooklyn announced plans last month to shutter 26 parochial schools in Kings and Queens counties, observers called it the end of an era. Enrollment had nosedived, teachers were in short supply, and parish costs continued to climb.

New state statistics show, however, that other religious schools – notably Jewish and Islamic institutions – are increasingly popular.

In the 1999-2000 year, the city had 238 Jewish schools, and by 2003-04, there were 258, according to figures from the state Department of Education. During the same period, the number of Islamic schools registered with the state agency rose from 10 to 13. Meanwhile, the number of Catholic schools declined from 361 to 353.

Many of New York City’s Islamic and Jewish schools report waiting lists, overcrowded classrooms, and tuition hikes. In Brooklyn’s Boro Park, where a Catholic school, St. Catherine of Alexandria, is set to close, no fewer than six chasidic private schools share a single square block. How come?

The simple answer is demographics. While Irish- and Italian-American families flocked to the suburbs in recent decades, Orthodox Jewish communities have tended to grow more concentrated. The city’s Jewish population has remained relatively constant, but the neighborhoods of Boro Park, Flatbush, Crown Heights, Williamsburg, and Far Rockaway have become established centers of Jewish life.

New York’s Catholic population is actually on the rise, according to statistics from Penn State’s American Religion Data Archive. As of 2000, there were roughly 3 million Catholics in New York, along with 1 million Jews and 167,000 Muslims. The new Catholics, largely immigrants from Latin America and Southeast Asia, are less likely than their American-born counterparts, however, to be able to afford tuition at a parochial school, which averages around $3,000 a year, according to a spokesman for the Brooklyn diocese, Frank DeRosa.

Other subtler factors are also involved. While Catholics once felt compelled to protect their culture, that imperative is largely gone, a professor of religious studies at New York University, Frank Peters, said. Orthodox Jews and Muslims, in contrast, still feel that they must battle for survival.

“There has to be a balance between your fear and the amount of money you’re willing to shell out,” Mr. Peters said. Even relatively poor Orthodox Jews find a way to send their children to private yeshivot and day schools, according to the executive vice president of the Board of Jewish Education of Greater New York, Rabbi Martin Schloss.

“The Orthodox community has moved to the right,” Rabbi Schloss, who is chairman of the state’s Advisory Council for Nonpublic Schools, said. “The farther right you go, the greater the demand and need for intensive Jewish education.” As the communities grew stronger, more schools appeared, so that now, he said, yeshiva “is a must and a given, not a choice.”

A mother on the Upper West Side, Jeannie Fisher, agreed. She and her husband, Scott, both attended yeshiva themselves and want the same for their 2-year-old daughter, Sophie.

“To me, it would be unimaginable to send her to public school, because religion is such an important part of our lives and our family history,” she said.

Yeshiva, she hopes, will help reinforce what Sophie learns at home. “Being observant makes you stand out,” Ms. Fisher said. “If there’s a party and there’s a pepperoni pizza, it’s hard for an 8-year-old to explain why she can’t eat it.”

Muslim children face similar pressures, according to an administrator at Al-Noor School at Brooklyn, one of the city’s largest Islamic academies.

Over the past decade, Al-Noor’s student body has grown, the school’s assistant principal, Ahmad Hamid, said, to 700 from 300 students in kindergarten through grade 12. It now has 27 classrooms and 60 full-time employees. Tuition averages $3,500 a year.

Islamic schools are burgeoning,

Brother Hamid said, as more immigrants arrive from Pakistan, Bangladesh, and the Middle East, and first-generation Arab-Americans become teachers. “At first, they couldn’t function as schools. The teachers at the beginning were not American-trained, American-born,” he said. “Now they are quite familiar with the new standards and doing a good job with it.”

In addition, like the nuns and priests who once ran Catholic schools, Muslim teachers at Al-Noor are willing to work for meager wages.

“It’s a safe environment,” the assistant principal said. “You’re not lost like a drop of water in the ocean. Even if you’re not properly compensated financially, you die and go to heaven.”

Like Rabbi Schloss, Brother Hamid considers religious education a necessity for Muslim children. “Things we wouldn’t tolerate here are quite acceptable in public school: smoking, drugs, hazing, dating,” he said. At Al-Noor, girls can wear their hijab, the traditional head scarf, without being teased, he said, and won’t be “pounced upon by people who would take advantage of them.”

Mr. Peters, the NYU professor, understands that sentiment. “Muslims are the new kids on the block,” he said. “They haven’t figured out yet how to deal with secular culture. One of the ways to deal with it is to try to build up a system that slows assimilation.”

Once, many Catholic parents felt much the same way. “My mother was a single mother working a very menial and limited job, but she sent all three of us to Catholic school,” an administrative assistant in her 50s, Claudia Seegraber, said. “That was her priority, and that was everyone’s priority. People didn’t go on big vacations or have 16 TVs in their house.” Now, she said, many Catholic parents “don’t want to make that sacrifice – they want to go to DisneyWorld.”

Still, Catholic schools are far from dying out. Mr. DeRosa of the Brooklyn diocese points out that new school openings, while significant, don’t necessarily herald a major shift. “They never started with the numbers that we have,” he said.