A new Bronx charter school is looking for the children who challenge most other schools: those who are homeless, from low-income single-parent households, English language learners, or suffering from disabilities that put them at a disadvantage to succeed in school.

Surprisingly, they are having difficulty attracting them.

The new school, the Children's Aid College Prep Charter School, is the first full-fledged school created by the Children's Aid Society, a charity organization that primarily provides social services for children.

The school is slated to open in the South Bronx in the fall with 120 kindergarteners and first graders, and Children Aid Society officials said they will give priority to children who have special challenges or needs. In fact, they said, they are giving them priority in admissions.

"Poverty shows up in classrooms every day," said Drema Brown, vice president of education for the Children's Aid Society. "But this school is a concerted effort to organize the needs we can anticipate up front."

But with the lottery to determine admission to the school just two months away, officials are concerned that they are not seeing enough applicants. The school was announced in September, although officials have not yet mounted an advertising or promotion campaign. They have been getting the word out through staff members to the agency's clients.

Agency officials also said they may have turned off some prospective parents by describing the special lottery system used to admit students as "weighted," Ms. Brown said.

"Reaction in the community was not great," said Ms. Brown, who was principal of P.S. 230X for four years and trained new principals at the New Leaders for New Schools program. "The reality is we are trying to create greater equality."

So they adopted new language and now call the weightings "preferences."

The school has identified seven preferences. Each preference associated with a child will result in an additional ping pong ball being added to the drum used in the drawing -- a standard method of filling charter school seats.

Parents can apply to have their child entered into the lottery by filling out the charter school common application. They can also call 212-949-4938 for additional information.

Classes will have roughly 20 students, with two teachers to a room. Both the school day and year will be longer than those in traditional public schools to maximize learning time.

For the last 19 years, the Children's Aid Society has operated programs or provided services in 20 New York City schools, as part of a special partnership to create so-called community schools. At these schools, the Department of Education manages the core academics, while the Children's Aid Society provides "wrap around" services like health clinics, parent support and after school programs.

The South Bronx school is the first time the agency will provide a full academic and social experience for students.

The new school will move into a building on Prospect Avenue, in the Morrisania section, with Public School 211 and Intermediate School 318. The society already has a presence in the building, providing services in P.S. 211.

Betty Gonzalez Soto, the principal at P.S. 211, said her school has a good relationship with the Children's Aid Society. Maria Lopez, principal of I.S. 318, was not available.

The society school still needs a principal. Ms. Brown said an offer was made to a candidate who is a principal at another Bronx charter school. Once a principal is on board, they can start hiring teachers and staff, she said.

Pedro Noguera, professor of education at New York University, said the Children's Aid Society is creating the kind of charter school that should be emulated. Mr. Noguera, who as a member of the SUNY Board of Trustees, which authorize charters and approved the Children's Aid Society's application last summer, resigned the board earlier this month, in protest, he said, over the direction that charter schools are taking.

"This is exactly the kind of role that charters should play in New York City and elsewhere," said Dr. Noguera. "They have a strong track record and are taking on a very hard population of students to teach." 

Richard Buery, president and C.E.O. of Children's Aid Society, said the agency will make a push in the weeks ahead to get the word out about the school.

"We're concerned with the development of the whole child," said Mr. Buery. "We are designing a school that serves children who are not served in public schools right now."