Virginia Gov. Charles S. Robb today abandoned his earlier refusal to compromise and said that he will sign a bill to raise Virginia's beer-drinking age from 18 to 19.

Robb, who had insisted that the legislature raise the age to 21, made his announcement minutes after the Senate Rehabilitation and Social Services Committee voted 10 to 5 to reject his original bill and unanimously voted to back a substitute measure that would increase the age to 19.

The governor's statement is expected to end legislative wrangling over the issue, but not necessarily remove teen-aged drinking and driving as a political issue in the state. Leaders of grass-roots groups who have waged intensive lobbying campaigns for Robb's proposal said that they are unhappy with the compromise and that they expect to return next year to press for raising the minimum age to 21.

"I am very unhappy," said Patti Herzog of Fairfax County, who is vice-president of Mothers Against Drunk Driving (MADD) and whose daughter was killed by a teen-aged drunken driver just 14 months ago.

"It's over for this year," said Herzog of the campaign to raise the age to 21 . "But we don't think 19 is better than nothing. I'd rather they had done nothing."

James Burnett of Arlington, chairman of the National Transportation Safety Board, said that he also was disappointed by the decision.

Robb's spokesman, George Stoddart, said that the amended bill "sends the right message to the people of Virginia that the state is serious about drunk driving." Furthermore, Stoddart said, the new bill will have the same effect as the Robb version, which would have raised the drinking age to 21 in one-year increments over the next few years.

Robb decided that a compromise was necessary, Stoddart said, after several senators had warned the governor that 10 of the 15 committee members were prepared to kill his bill.

"The political situation we were confronted with was that we were making no progress on this issue at all this year," said Sen. Dudley J. (Buzz) Emick (D-Botetourt), one of the legislators who had talked to the governor.

Sen. Charles L. Waddell (D-Loudoun), who voted against the Robb proposal in the committee, said, "Each of us took a calculated risk in doing what we did, but we did what we thought was right."

Some of the legislators, Waddell added, were concerned that their votes might become an issue during their election campaigns this fall.

Earlier this month the committee had killed two similiar proposals that also would have raised the drinking age to 21. Many senators said that they felt the proposal was unenforceable, as well as being unfair to youths old enough to serve in the military, to vote and to marry.

In return for Robb's compromise, Stoddart said, Emick agreed to support the recommendations of the Governor's Drunk Driving Task Force, which is studying the drinking age and may recommend raising it to 21 in time for next year's legislative session. That task force is chaired by Del. Mary Sue Terry, (D-Patrick) who sponsored Robb's bill and helped shepherd it through the House, where several proposals for a minimum age of 19 had received strong support.

During a brief hearing before today's vote, while college students and the relatives of drunk driving victims looked on, Terry pleaded in vain with the committee to pass the measure. Some legislators said, however, that the agreement among Emick, Robb and Terry to compromise on the age of 19 had been reached last night.

The logic for having the same age is irrefutable,"Terry told the committee today that Virginia currently has three legal drinking ages: 18 for drinking beer in bars, 19 for buying it in grocery stores and 21 for purchasing wine or liquor.

"The logic for having the same age is irrefutable," she said. "A lot of young people are concerned about losing the right to drink for one two or three years . . . . What we're really talking about is a right deferred, not a right denied."

After the committee voted to kill Robb's proposal, Terry agreed to accept the compromise and the senators accepted an amendment that would require newly licensed Virginia drivers to show they have passed an alcohol education course.The bill also provides that anyone less than 19 years old who is found drinking could lose his or her driver's license for up to a year.

Terry said later that "as a realist" she supports the compromise, which she called "a small step".

Although the compromise angered the Northern Virginia MADD group, it pleased a competing Norfolk-based lobby, Many Against Drunk Driving, which also uses the acronym MADD.

"It may be a small step, but I'm pleased," said Lillian Devenney, vice-president of the Norfolk group, who had favored retaining the current 18-year-old minimum in bars but raising the age for buying beer to 21.