ASHINGTON, Aug. 27 — It looks like a 7-Eleven in a box.

Early this morning, as the restaurants and clubs were shutting down in the Adams Morgan neighborhood here, a young waiter named Rick Roman joined a crowd gawking at the new attraction on the sidewalk: an 18-foot-wide vending machine.

Mr. Roman looked through the glass at the dozens of products — bottles of olive oil and milk, cartons of eggs, chicken sandwiches, paper towels, detergent, diapers, pantyhose, toothpaste, condoms, DVD's — and realized what he absolutely had to take home at 12:15 a.m. After he inserted a $10 bill and punched numbers on a screen, the crowd watched a metal bin rise to collect a package of razor blades from one shelf and a can of shaving cream from another.

One bystander muttered about "dehumanizing technology," but most oohed approvingly as the bin swung back to deposit the razors and cream in front of Mr. Roman. The machine even provided a plastic bag.

"It's pretty cool," Mr. Roman said. "Whoever made this is a genius. A guy in the store can make a mistake or give you a hard time, but not the machine. I definitely prefer the machine to a person."

This machine, the Shop 2000, is the only one operating in America. Some locals call it an eyesore, but others are happily posing for photos in front of it, and in its second week of operation, more than a few people are feeding it their cash and credit cards. If the test in Washington goes well, its manufacturer predicts a new era in convenience for Americans, as do rivals working on similar machines.

These kiosks, known as automated convenience stores (a better name might be RoboShop), are similar to multipurpose vending machines already operating in Japan and some cities in the Netherlands, Belgium and other European countries where labor is expensive and real estate is scarce. Those constraints are now being felt by American retailers. A study by the National Association of Convenience Stores suggests that a shortage of labor will be one of the industry's biggest problems in coming years.

"With this machine, you eliminate most of your labor costs as well as problems with theft," said Hettie Herzog, president of the machine's manufacturer, Automated Distribution Technologies of Exton, Pa. "Plus it goes into a small space. A typical convenience store takes up 2,500 square feet, but for this you need only 200. It's perfect for places that get a lot of foot traffic — busy sidewalks, dormitories, train stations, office buildings."

Ms. Herzog, who got the idea for her machine from one in Belgium selling groceries, tested it last year at a gas station in York, Pa. Drivers there did not provide enough business, but there were better results at a test at a parking lot near Howard University here this year, and she predicted strong sales from pedestrians now walking past the machine at the edge of a parking lot at a corner of 18th and California Streets in the city's northwest section.

The prices at the machine — $1 for a can of soup, $2 for a half-gallon of milk, $4 for a box of Cheerios — are in line with those at nearby convenience stores, although the selection is limited. Ms. Herzog said her machine can stock about 200 products, less than a tenth of what is found in a typical convenience store.

"You can track sales remotely by dialing the machine's computer to find out exactly what's left of each item," she said. "If the machine stops or has a problem, it will call your pager and e-mail you."

This machine is being greeted cautiously by operators of traditional vending machines, as is a drive-through automated store under development by another company.

"Automated C-Store: Vending's Partner or Competitor?" was the headline of a recent article in the trade journal Automatic Merchandiser. Industry veterans note that there have been unsuccessful efforts to move beyond the "four C's" — candy, coffee, cold drinks, cigarettes.

The Keedoozle, a self-service grocery store using a conveyor belt, failed in the 1930's. A more successful predecessor, the Horn & Hardart Automat offering hot food, was supplanted by fast-food franchises.

"One reason full-line vending machines have not swept the United States to date is that we have had a large population of entrepreneurial immigrants eager to operate convenience stores," said Timothy Sanford, editor of the trade journal Vending Times. "But it's getting very hard to find capable sales staff, and it doesn't make sense for them to spend valuable time selling simple items that don't require their expertise."

RoboShops have advantages, he said. "You don't need bathroom space for employees and aisles for customers. You don't need to worry about someone pulling a gun on a clerk. The public needs to get used to these kinds of stores, but I think it's inevitable that they will. People are already accustomed to automatic teller machines and self-service gas pumps. When they know what they want, they want to get it without waiting in line and worrying about whether the clerk's had a bad day."

Those attitudes were evident in a survey by the National Association of Convenience Stores. When asked which factors affected their decision to shop in a convenience store, people ranked "friendly, helpful service" well below "convenient location" and "fast in and out of store." Way down the list, in 13th place, was "pleasant store ambience."

Still, some people watching the machine defended stores with clerks. "I'm concerned about the people this is going to put out of work," said David Bottoroff, an editor. "It's shockingly inhumane, and it's also an eyesore. I'd much rather see a storefront here than this ugly box."

Other late-night machine-watchers shared his feelings and complained about lazy Americans' obsession with convenience, but the critics seemed to be few. "Awesome" was the typical review. "Like something from the future!" shouted the leader of a group heading home from a bar.

Even Mr. Bottoroff paid the machine a compliment. He did not approve of it, he said, but since there were no competing stores open on the block at this hour, there might come a night when he buys a DVD or popcorn or something. "I have to admit it's convenient," he said.