Responding to the theft each month of $10,000 worth of food stamps delivered by mail, Montgomery County will change its delivery system next week to require recipients to go to government offices to claim the benefits.

The move by Montgomery officials follows similar policy changes across Maryland's urban areas. As in much of the country, food stamps are a consistently easy target of theft or fraud. Thieves steal them from mailboxes or the recipients themselves may use the stamps, then claim they were stolen to receive double the allotted amount.

"We finally had no choice," said Carol Johnson, assistant director of the county social services department. "Our losses were staying too high. It means a lot of people will have to be inconvenienced."

Starting Wednesday, most of the 5,500 families receiving food stamps in Montgomery will have to go to one of three county government offices to collect the stamps. Mail service will continue for senior citizens, the disabled and others who can make a case that they would have an especially difficult time traveling to the offices.

Montgomery County officials delayed making such a change in hopes that the thefts would decrease. But in the past year, the county lost $124,000 of the $9 million in food stamps issued -- a figure that postal officials say is higher than average and that federal agriculture officials said had to be reduced. In the fiscal year ending June 30, 1987, the last year for which figures are available, Maryland issued food stamps worth nearly $36 million and reported losses of $248,434.

Many jurisdictions, such as Prince George's County, discontinued mail service several years ago in favor of a system in which recipients are issued a photo identification card that they present at five check-cashing centers to obtain food stamps. The centers receive a fee to provide the service.

Montgomery has found it too costly to make similar arrangements.

Montgomery and state officials said new technology may soon change all that and allow recipients of food stamps and other aid to obtain benefits with a special bank card.

As part of a pilot program that officials hope to expand statewide, about 5,500 Baltimore households now use a special card that works on the MOST automatic teller system. Users can go to certain grocery stores, present the card and have the amount they purchased deducted from their monthly allotment.

The system -- believed to be the only one of its kind in the country -- makes food stamp theft by mail nearly obsolete and affords the poor quicker, more convenient ways to shop and conduct their finances. With the same card, those receiving Aid to Families with Dependent Children also can obtain that benefit.

In January, state officials will start to gather data on the cost of expanding the program, called the "Electronic Benefit Transfer System," and including other aid, such as Social Security, on the card.