The D.C. voucher program did not receive enough applicants from public schools to fill all the slots available, and some of the children who will receive the federally funded tuition grants already attend private school, officials said yesterday.

In all, about 1,200 low-income children will be given the private school scholarships this fall, of whom roughly 200 are already in private school. Officials with the Washington Scholarship Fund, the nonprofit group running the program, also announced that 50 private schools have agreed to participate.

The $14 million initiative, the nation's first federally funded voucher plan, provides grants of up to $7,500 per child toward tuition and other education expenses at private or religious schools.

When Congress debated last fall whether to launch the plan, supporters argued that the measure was sorely needed in the District so children could escape its low-performing public schools. Although public school students have priority in the awarding of vouchers, the legislation allows those already in private school to receive money if they meet income guidelines.

Officials with the Scholarship Fund said more public school children would have applied if organizers had had more time to publicize the program. The five-year program was approved by Congress in January, and the nonprofit group was chosen to run it in March.

The fund expects to recruit more public school applicants for the 2005-06 school year and also increase the number of slots available, said Sally J. Sachar, the group's president and chief executive. Many private schools had filled most of their spaces for this fall by the time the program was launched.

Congress provided enough money to serve at least 1,600 students in the first year. Officials said yesterday that they received 1,200 applications from eligible public school students and 521 from eligible children already in private school. Although organizers could have filled the program by accepting all the private school students who applied, Sachar said her group decided -- in consultation with the mayor's office and the U.S. Department of Education -- to provide grants to only about 200 private school children.

She said no more than about two-thirds of the available voucher money will be distributed this year, with the rest being rolled over to 2005-06. She estimated that 500 to 900 additional slots for voucher students will be available next year.

When told yesterday how many private school students would be participating in the first year, voucher opponents criticized the allocation of the money.

"It's outrageous," said Ralph G. Neas, president of People for the American Way. "Federal dollars that could be used and should be used to improve struggling public schools are now being used to subsidize the education of children already in private schools."

But Sachar argued that private school students who meet the income guidelines for vouchers -- a household income of no more than 185 percent of the federal poverty limit, or about $36,000 for a family of four -- also deserve the assistance.

"They are scraping it together to go to these private schools," she said, adding that some of the students had been in private school for only a year. "They're being penalized in a sense because they already have taken that step." She said the number of voucher recipients from private schools -- 200 -- was chosen based on "what seems fair."

The small number of families taking advantage of the voucher program is a sharp contrast with the large number who have left the regular public school system in recent years to attend public charter schools, which now enroll about 13,700 students. In interviews before the voucher application deadline, several parents said they were only vaguely aware of the program and unfamiliar with the rules for applying.

Rep. Thomas M. Davis III (R-Va.), a sponsor of the legislation, said he would have preferred that more public school students apply. But he said that demand exists for vouchers and that more time is needed to advertise the program. "You're still getting the word out," he said. "You need three or four years."

D.C. Council member Adrian M. Fenty (D-Ward 4) disagreed, saying the fact that more families did not apply shows that vouchers are not needed. "It very clearly says there is not a lot of support for vouchers," said Fenty, who opposed the bill. "Where is the rush? Where is the onslaught of people who were supposed to come out and take part in this process?"

Overall, the number of public school applicants is about the same as the number of slots that private schools have set aside. But the situation varies widely by grade level, with too many applicants for slots in grades six through 12 and not enough applicants in kindergarten through fifth grade. As a result, some of the available spaces will go unfilled, and officials estimate that about 1,000 children from public schools will receive grants.

In grades where there are more public school applicants than slots, voucher recipients will be picked through a lottery to be held next week. A second lottery will be held if a particular private school has more applicants than slots.

A separate lottery will be held to select which students now in private school will receive vouchers.

Voucher recipients, whether coming from private or public schools, will not need to reapply in subsequent years.

The low number of public school applicants also is an issue for researchers. Federal officials had planned to assess the program's effectiveness by comparing the performance of voucher recipients to that of students who wanted grants but were forced to remain in public schools. Because of the low number of applications, such a study will not be possible in the first year, federal officials said.

Grover Whitehurst, director of the Institute of Education Sciences, a branch of the Education Department, said officials hope that enough students will apply in the next round so that meaningful research can be conducted in the program's second year.

Officials with the scholarship fund said that of the 50 private schools participating in the voucher program, 30 percent are non-sectarian, 44 percent are part of the Archdiocese of Washington and 26 percent are other sectarian schools.