BALTIMORE (AP) _ Maryland on Wednesday became the first state in the nation to require public school students to perform community service to graduate.

The plan passed by the State Board of Education requires students to complete either 75 hours of community service or a program designed by local school officials and approved by the state superintendent of schools.

The changes take effect for incoming ninth-grade students in the 1993-1994 school year.

The community-service requirement will help teach students the values of citizenship and show that they are contributing members of society, said Kathleen Kennedy Townsend, president of the Maryland Student Service Alliance, which helped develop the plan. The alliance, a program of the state Department of Education, oversees school community service programs.

''It's a way to show they can make a difference,'' she said.

Opponents of the community requirement argued that community service and volunteerism should be encouraged rather than imposed.

''We don't feel it is appropriate to coerce paid labor just because they're children,'' said Jane R. Stern, president of the Maryland State Teachers Association, state affiliate of the National Education Association.

''Once you make it a requirement, you lose the meaning of volunteering; it's just doing time,'' she said.

Ms. Stern said the teacher's union may challenge the requirement in court.

Ms. Townsend said the Maryland program could be the start of a nationwide trend. South Carolina has asked about developing a similar plan and the District of Columbia will require its students to perform 100 hours of community service in the fall, she said.

School officials in Atlanta, Detroit and Springfield, Mass., already require their students to perform community service.

Starla Jewell-Kelly, executive director of the National Community Education Association in Arlington, Va., said mandatory community service is needed to help rebuild cities.

''Communities are breaking down. We don't have that sense of each other; you can see that in the breakdown of inner cities,'' she said. ''People need to feel responsible for their community, to care about the city and the streets.''

Community service was the most controversial part of a comprehensive package approved by the State Board of Education that overhauls graduation requirements throughout the state. The board also increased the number of total credits required for graduation from 20 to 21. And students will be required to take algebra and geometry, technology education and social studies.

The 10-member board passed the education package unanimously.

But Jamie Kendrick, a student representative on the board who also volunteers for a drug and alcohol abuse program, said the community service requirement was an insult to students.

''I kind of see it as a slap in the face. If students want to be involved they should be able to, but it should not be something required,'' he said.

Rich Cairn, director of policy at the National Youth Leadership Council, said mandatory community service for public school students is unrealistic.

''I really question the quality of participation when it becomes a graduation requirement,'' said Cairn, who helped develop a voluntary community service program in Minnesota. ''Are they really going to flunk a kid if he or she doesn't have any service? I can't imagine schools actually doing that.''

Nancy Grasmick, state superintendent of schools, said it won't be known how much the new requirement will cost the state until local districts submit their plans.