Shelly Rodante works in an office park in Landover and used to leave her 21-month-old daughter Jillian with a baby sitter near her home in Annapolis. That arrangement was fine most of the time, she said, but whenever a minor crisis occurred, she felt helpless to do anything about it, because home is 45 minutes away.

Last week, that all changed when she was able to place her daughter in a day-care center next door to her office, in the first such facility in a corporate setting in Prince George's County.

Being able to enroll Jillian at the Metro-East Children's Center, she said, was "the best thing that's ever happened to her. Being so close by is wonderful. I can keep an eye on her and still not miss work."

The nonprofit day-care center, located within walking distance of the New Carrollton Metro station in the Metro-East office park, operates from 7:45 a.m. to 6 p.m. Monday through Friday. The five-classroom facility has a capacity for 67 children; last week, about a dozen had been enrolled. About 6,000 people work at the office park.

The children's facility has a separate entrance on the ground floor of a five-story building that was designed to incorporate a day-care center. The only outward sign of the center is a fenced-in playground across from the parking lot.

The idea is to keep as low a profile as possible, said Cheri Sheridan, president of Play And Learn Corporate Child Care Inc., which operates the center.

"We are in a professional office building, and we don't want to have kids racing Big Wheels through the atrium," she said. The center's walls are painted in subdued blues and pinks, and the hallways are decorated with framed prints from the National Gallery of Art. "You won't find Big Bird painted on the window," Sheridan said with a laugh.

Prince George's General Hospital has sponsored a day-care program for its employes since 1975, and the county government plans to open a day-care center for its employes in 1986, but the Metro-East facility is the first in a generalized business environment in the county.

The center, which enrolls children ranging in age from 10 weeks to 5 years, follows a "development curriculum," said Lynne Doeler, director of the facility. The curriculum lists various stages of development that a child should reach on a month-by-month basis, and ways to encourage the child to reach them.

Fees range from $100 a week for infants under 2 to $82 a week for children 24 to 36 months old, and $75 per week for pre-schoolers older than 36 months.

Phyllis Diggs, who coordinates child-care issues for the county executive's office, said the opening of the facility comes at a time when there is "a critical need" for day care in the county.

There is "a definite shortage of available slots for young children," she said. There are about 45,000 children in Prince George's under the age of 6, she said, and about 18,000 slots available in licensed day-care facilities in the county.

Most of the remaining children are taken care of independently, she said, but she estimated that as many as a fourth of those have "great difficulty" finding adequate day care.

The day-care shortage is area-wide, said Abby Martin, a spokeswoman for the U.S. Labor Department. While many federal government departments and a number of hospitals provide day-care services for their employes, most businesses do not, she said.

Prince George's County school spokesman Brian J. Porter said the county's six new extended day "work place schools" should somewhat alleviate the day-care problem in Prince George's County. He said about 550 elementary students are enrolled in the work place schools, which are open from 7 a.m. to 6 p.m. and provide elementary school students with academic services and day-care before and after school. Of those enrolled, close to 150 are first-grade students, he said. The fee is $27.50 per week.

Sheridan, 29, contends that corporate day-care is part of "the office environment of the '80s," and she predicted that day-care benefits will become as common as health-care benefits are now.

The reason, she said, is that corporate day-care serves all concerned. For the children, "It lets them become a part of mom and dad's life, both at home and at work. They can actually see mom and dad walk in with their briefcases in hand."

For parents, the convenience of having their children so close by "will, hopefully, bring them peace of mind," she said. For employers, convenient day care will "help reduce turnover and absenteeism and increase recruitment," she said.

"Corporate day care is indicative of what we'll see in the future, but at the moment, there are not many," said Ruth Crone of the Metropolitan Washington Council of Governments.

"Businesses are finding they need to do it, not for altruistic reasons, but to keep their employes," she said. "It's definitely the wave of the future."