For years, they fought. And when laws securing public education for the handicapped were signed in Annapolis and Washington, the Montgomery County parents who had led the battle thought they had guaranteed a future for their mentally retarded children.

Ten years later, they know there are no sure bets. What the law now provides for their children is a public school education through age 21. What comes after their children reach 21 is a scramble for survival in a state where nearly 8,000 handicapped persons already receive some kind of support but another 3,500 who are older than 21 -- 2,600 mentally retarded and 900 other developmentally disabled -- have no day care, institutions or jobs to fill their days.

Maryland parents are not alone in their struggle. Virginia has a waiting list of 1,500 mentally retarded persons older than 21 who need residential services and 1,800 who need day programs. The District of Columbia, which has had more success in creating day programs and has only 10 persons on a waiting list, estimates that 190 mentally retarded persons are without needed residential programs.

A Department of Health and Human Services report estimated in April 1984 that, nationwide, 90,000 developmentally disabled people graduate from school each year and need support programs of some kind. How many find services is not known.

"What are these children supposed to do when they reach 21 -- die?" asked one mother, Isabel Rosendorf, who says she will have to quit her job as a clerk-typist to look after her severely retarded daughter because Montgomery County schools cannot take her daughter back into classes this fall.

For many of these children, their last day of school indeed means the demise of learning as they know it. No longer are they reminded of the simplest skills -- such as chewing their food properly and reaching for toys. No longer do they face the challenges of working with plants, following instructions, or preparing food with classmates. It is an end to the therapy they thought was an unquestioned part of their days, to the routine of instruction and stimulation, to even the simple pleasure of a ride on a school bus.

For their parents, graduation day becomes a sad benchmark to a new life -- one in which they watch their children, without the daily reinforcement of schooling, lose basic skills that took years to acquire and wonder how, years from now, their children will survive. Parents who have jobs cannot give the full-time supervision that these children received in school.

"Sometimes when I describe the most recent horror story detailing the lack of services, I wonder if it doesn't sound kind of hysterical," said Ralph Moore, a lawyer who led the fight more than 10 years ago for a state law to provide public education for the handicapped. A member of the Montgomery County Association for Retarded Citizens, Moore again is leading a court battle to increase state dollars for these students after they reach 21. "The situations -- when they fall apart -- are kind of terrible," he said.

"I don't think parents are expecting too much," Thomas O'Toole, director of special education for Montgomery schools, said about the increasing demand for adult services. "The public law certainly did raise expectations."

Recognized by many as a county that is sensitive to the needs of the handicapped, Montgomery County led a statewide battle to gain the judicial order in 1973 that provided public education for the handicapped. That law became a model for federal legislation in 1975.

Since that time, Maryland has provided millions of dollars, as much as $80 million last year, to supply family support, community support and direct placements in appropriate community programs for the mentally retarded, physically handicapped and other developmentally disabled in the state. But a quick check of state budget figures shows that the money -- which in the last two years has been enough to provide 500 new placements for the mentally retarded -- has not been enough.

"The state has given money, but the waiting list continues to grow," said Lois Meszaros, director of Maryland's Mental Retardation and Developmental Disabilities Administration. "Until this year, we haven't been able to keep up with the number who have graduated."

This year, Maryland has added $4.5 million to its appropriations for the mentally retarded over age 21. That money will translate into 630 new residential or program openings, a number that seemingly should answer the needs of those just graduating and those who have been waiting for programs.

Not so. Because of a philosophy of mental health care that the handicapped should live in the least-restrictive settings possible, Maryland has tried to empty its institutions for the mentally ill and the mentally retarded and place them in group homes or day programs.

That effort has meant the closing of the Phillips Program in Anne Arundel County and the Henryton Center in Carroll County during the past two years, both formerly institutions for the retarded. In addition, Rosewood Center in Owings Mills, near Baltimore, the state's oldest and largest institution for the mentally retarded, has been ordered to reduce its population. An institution that two years ago had 1,300 residents will have 600 this fall, state officials said.

People leaving the institutions have been given priority for placement in community-based programs. And there lies the problem for the mentally retarded now leaving public school.

Nearly half of the new program openings created this year by the state will be given to people leaving institutions. The remainder of the openings will barely match the 300 students leaving public schools.

State officials estimate the amount of money needed to provide all the necessary services for the mentally retarded could easily amount to another $52 million.

That is a figure that makes even the most ardent of advocates for the mentally retarded cringe -- and has county governments, schools and businesses working together to create jobs and activities to answer the needs for the mentally retarded in their own communities.

"Now is almost like a coming of age for the parents who helped push for the original advancements in education for the handicapped," Meszaros said. "Now their children are graduating. And again they are seeing what doesn't yet exist."

Rosendorf, a single mother from Rockville, has experienced both the benefits and the limits of the law since her daughter Diane was born severely retarded 21 years ago.

Before laws providing public education for the handicapped were passed, Rosendorf would drive 40 miles round trip every day to get her daughter the proper therapy. Once the law was reality, she came to rely on the government as her partner in a consuming effort to keep her child at home.

"You have a child and it's yours. I wasn't going to put her in an institution. I am her mother," Rosendorf said. "I decided I couldn't have any more children in order to take care of this one. I've never regretted that decision. I see now how she has taken over my life."

For the past eight years, Diane Rosendorf has attended day classes at Longview School, one of three Montgomery County public schools for the mentally retarded. In April, she turned 21.

Isabel Rosendorf said she has not been able to find a day or vocational education program, sponsored by a private or nonprofit group, that has room for her daughter. Even if a vocational program is found, Rosendorf said, she would refuse to place her daughter in a center that would provide less therapy than what she has come to expect from the public school system.

"I don't know what I'll do," Rosendorf said, her voice growing strident in anger. "Diane needs therapy. It is so necessary to her . . . . Lots of people say, 'Isabel is a fool. Why does she have that child at home? She should be institutionalized. She's sacrificed her life for her.' "

Rosendorf reaches over and touches her daughter. The next words are restrained in emotion. "Do you think any stranger would have the patience? Do you think any institution would give her the care she needs?" Later, Rosendorf speaks softly. "What happened to my beautiful daughter? I had so many plans and dreams for her."

Dr. Mary Jane Wagstaff is a mother of five, including a 16-year-old blind and retarded son named Ricky. A public health physician, Wagstaff and her husband Chester, also a physician, had always felt that they were able to answer the needs of their children and maintain their jobs.

But this year, the Wagstaffs decided they needed to make some changes. Ricky, they realized, was getting older. In five years he will no longer be eligible for public school at Longview. Mary Jane Wagstaff quit her job to spend more time with her son and more time searching for adult day programs that he could go to in the future.

Already, she and her husband are worried.

"Parents who kept their children at home and put them in public school now are finding that the parents who put their children in institutions are the ones getting the placements, getting the help," Mary Jane Wagstaff said. "And they were the ones who saved tax dollars by keeping their children at home."

Wagstaff has not limited her concern to her immediate family. For the past nine months, she has participated in a Montgomery County task force that has been researching ways that the handicapped can make the transition from school to community.

This month, the 28-member group of civic leaders, business people, schoolteachers and parents will present a report emphasizing the need for cooperation between the business community and the school system so the handicapped can find meaningful work or activities outside the home.

The report will recommend teaching the handicapped marketable skills that can lead to jobs or provide participation in community groups, and beginning that training three to five years before the students finish school. The report will say that a county board should be formed to help bridge the gap between prospective employer and school and that parents should be counseled and consulted as their children progress through their final school years.

"We've done vocational training all along but we haven't done it on a consistent or directed basis," said Margit Meissner, assistant for policy development for Montgomery schools. "And, certainly, there hasn't been a strong bridge built with the business community."

Montgomery County Executive Charles Gilchrist made a pitch during the last budget session for more social services during a time of federal cutbacks. And in its final budget this year, the County Council allotted $60,000 to develop plans and placements for the handicapped.

On the state level, some legislators are scheduled to meet this month in Annapolis to discuss funds for day and residential placements. A hearing has been set for Oct. 8 to discuss how handicapped students around the state are making the transition between school and adult life.

This increased interest comes months after the Montgomery County Association for Retarded Citizens filed three lawsuits against the state that illustrated the plight of three mentally retarded adults who have not been placed in residential settings because of the lack of state funds. The suits are expected to take months, perhaps years, before being resolved.

"What we have now is a situation where people regress and lose the skills they worked hard to achieve," said Rob Romagna, director of program services for the association.

"What we want is an end point. So five years from now, we can have enough slots for the people who need them."