The Moss Free Clinic waiting room often looks like a big-city bus at rush hour, with seats and laps full and standing room scarce. At other times, it becomes the clinic's gym, where participants in a health care class fight through "couch potato aerobics" amid waiting patients flipping through magazines. One recent evening, Shirley Barnwell of Spotsylvania was among those waiting.

Unemployed and without health insurance, Barnwell, 51, said she wasn't in the habit of going to the doctor "unless I got really sick -- then I'd go to the emergency room." But three years ago, she found herself exhausted and couldn't function or care properly for her three children, and a cousin told her about the clinic, where health care is free for those who have no other coverage.

Doctors found that she had high blood pressure and immediately put her on a regimen of medication, a low-sodium diet and extra potassium. Now she comes into the clinic every two months to have her blood pressure checked and for regular dental or gynecological care, among other things.

"Sometimes I think about what I'd do if the clinic wasn't here. I don't think I'd be here," she said as her name was called.

In one seat after another, patients described a similar reliance on the Moss Free Clinic, one of 50 clinics in Virginia staffed almost completely by volunteers to serve patients who don't qualify for health care any other way -- a group typically characterized as "the working poor."

The number of patients at the Moss Free Clinic has increased 2 to 10 percent each year since it opened in 1993, and it plans to double in size next year -- primarily with financial support from the foundation of nearby Mary Washington Hospital. Because their own emergency room is jammed with the uninsured, hospital officials say it's simply good business to invest in a clinic for non-emergency care.

The decision to raise $10 million for a new clinic reflects what local, state and national free clinic officials say is a very recent acceptance that lack of insurance is a problem that is not going away.

In the early 1990s, when the Clinton health care plan was developed, it was "widely thought" that the issue would be addressed, said Mark Cruise, executive director of the Virginia Association of Free Clinics. When the plan failed to gain support in Congress, he said, people went mute on the topic. But it has resurfaced. "In the last two or three years, there has been a paradigm shift happening in the health care community that says the problem is here to stay," Cruise said.

Of Virginia's 50 free clinics, 12 opened between 1970 and 1992. The rest have opened since 1992 as the problem of uninsured patients has spread. Cruise said expansions such as the one planned at Moss are common these days.

Virginia has more free clinics than any other state except North Carolina. The state has very strict eligibility requirements for Medicaid, the federal-state health care assistance program for the poor. According to the Association of Free Clinics, Virginia's income limit for eligibility is lower than in all but eight other states. It also has an unusually broad law, passed in 1992, that gives volunteers at free clinics immunity from malpractice suits. Although other states have followed, Virginia's statute "continues to be the most expansive" in the country, Cruise said.

While donors to the foundation and clinic supporters met last week to celebrate the $4 million they have received toward their goal, clinic officials said even a beautiful new two-story brick facility won't meet the demand for service.

Last year, clinic workers and volunteers saw 1,400 patients for 6,500 visits and dispensed $1.3 million in free medications. But Karen Dulaney, the clinic's executive director, said at least 11,000 people in Fredericksburg and the four surrounding counties qualify for its care.

According to the U.S. Census, Virginia is about average in its population of uninsured: 13 percent. Maryland and the District are about the same.

Typical free-clinic patients don't qualify for Medicaid and are employed in jobs that don't provide insurance or that charge premiums they can't afford. They may be waitresses or construction laborers or salesclerks, said Patricia Wolfrey, senior development officer with the Mary Washington Hospital Foundation. "These folks don't have any other resources," she said.

With the Fredericksburg area increasingly becoming a suburb with a service economy, those jobs are a large percentage of employment, a fact that economic development officials fret over.

Although the nurses' station at the Moss Free Clinic is a desk in the hall and health classes are sometimes taught in the parking lot, volunteers (of which there are 400) and employees (of which there are 13) say there is an upside to the culture of a free clinic: a more relaxed environment, marked by an absence of bureaucracy.

Dulaney, who has been with the clinic for 10 years, said she encourages the levity.

"A lot of the [patients'] lives are sad," she said. "It makes the whole health care thing less stressful."

Among the 15 people who were there to see one doctor Wednesday night was Russell, a 59-year-old security guard. Russell, who spoke on the condition that his last name not be used, said he was grateful for the care he gets at Moss for his hernia, heart attacks, gallbladder problems and high blood pressure, though it's so crowded that even scheduled visits can take about four hours.

Russell had health insurance through his wife until their divorce landed him in a homeless shelter. The shelter directed him to the clinic, where he comes every three months.

"If the clinic wasn't here, I'd just live with it," he said. "And die with it."

Rosa Owens, 62, of Fredericksburg waits at the Moss Free Clinic. She said she found the clinic after her Medicaid coverage was cut off.Physician Steven Mussey sees Shirley King, 46, of Stafford on her first visit to the clinic. She left with a referral to a neurologist.