Last year, when a former South American exchange student left Adams-Morgan for Montgomery County, her friends accused her of going white bread on them.

"They said I was moving to WASP world," said the woman, who now works as a bank teller in Rockville. "I tell them, 'You're right, Rockville Pike isn't Adams-Morgan -- it's a lot cleaner' . . . . But it's just as interesting."

Rockville Pike -- the extension of Wisconsin Avenue north of the Capital Beltway through downtown Rockville -- spent the past decade cultivating a reputation for retail swank; at the same time, it has been undergoing an equally remarkable personality transformation. The WASP world along the Pike has gone ethnic, and suddenly the Pike's minority populations are no longer neglected, but instead are perceived as a selling point.

"We came here when it was cheap to rent , and even our customers acted as though we were invisible," said a naturalized Iranian, whose Rockville import store failed several years ago. "Now it is more acceptable to be ethnic ; soon it will be an asset."

Along the Pike, from the designer-label fortress of White Flint Mall to the Rockville Metro, a whole new generation of ethnic and specialty stores is flourishing. At Ritchie Center, for example, a health food store, a Christian bookshop and a Bob's Big Boy share a parking lot with Hispanic and Asian groceries, a Persian restaurant (which used to be Vietnamese) and a sushi bar.

Behind the all-you-can-eat American heartiness of the Chesapeake Bay Seafood House is a tiny strip housing a karate studio, another sushi bar and a Middle Eastern grocery and deli. Behind the booming Bradlee's discount store is the area's hottest semi-underground Latin disco.

One of White Flint Mall's attractions is a 12-booth food bazaar called The Eatery, which tries to keep up with what manager Maury Epstein calls "current fashions" in food. Italian, Chinese, Japanese, Korean, Mexican and deli are among the cuisines served up by experienced, appropriately ethnic employes.

And alongside Congressional Avenue, the New York, New York disco fronts the New Seoul grocery, an Oriental import store and the (formerly Hispanic, now Korean-owned) La Femina hair salon.

These stores are testimony to the Pike's drawing power. "Rockville Pike was our first choice because it is the main road," said Armando Garcia of the Las Americas grocery in Ritchie Center. "Our clients come from all over -- Gaithersburg, Potomac, Bethesda -- and every day our business increases."

Ali Sizdahkhani, who moved his Karpet King business from Seven Corners to Randolph Road 12 years ago, said that "as a retailer, you always want to go where the opportunities are developing, and Rockville is where the boom is."

The stores not only serve Montgomery County's increasing ethnic residents, but its ever more sophisticated middle-of-the road consumers as well. Sizdahkhani noted that several years ago, "you had to go over to Georgia Avenue" to buy the pita loaves that are sold in almost every market along the Pike today.

Hira Chand, who with his wife owns the Indian market in Ritchie Center, said that especially since the month-long Indian Folklife Festival on the Mall in Washington last summer, "Americans have been coming in to ask questions, and we give them recipes and explanations."

And his wife Sivitri Chand said she has noticed an increasing number of American, Oriental and Indian customers indulging in cross-cultural progressive shopping, "from Magruder's to Safeway to here."

Historically, Rockville Pike was a "white" Pike, the commercial strip for well-to-do residents from Potomac, about six miles away. The nearer residents of Lincoln Park, a black community in Rockville, were kept on the wrong side of the tracks -- cut off from Rockville Pike first by the railroad and, today, by the fenced-off Metro rails.

But in recent years, a number of ethnic communities have put down permanent roots in the Rockville Pike corridor. Scores of Korean families rent west of Congressional Plaza; as they get jobs and buy homes, their places are taken by more recent arrivals.

The Hispanic community, which used to look toward Wheaton as a shopping and social center, has spread west toward Twinbrook. And in the past two years, at least four Japanese restaurants have opened within a two-mile strip.

Although the Indian residents in the area are somewhat scattered, their social activities increasingly center on Rockville Pike and Richard Montgomery High School, where the major traditional Indian festivals are reenacted throughout the year.

"When we first came here 2 1/2 years ago , we were not so aware of so many ethnic businesses" in the area, said Hira Chand. "But it is certainly occurring now."

The increase in ethnic businesses and restaurants along the Pike has helped to solidify an underlayer of immigrant, especially Hispanic, labor. A White Flint Mall bartender jokes that she was hired because she speaks some Spanish "so I can communicate with the guys in the kitchen."

At the Crowne Plaza Hotel, foreign-born employes with poor English skills -- about a quarter of the staff of 400 -- are enrolled in a special language course conducted by school system experts.

Food service jobs are easy to find, says Ileana Herrell, Montgomery County's chief of minority affairs; there is a constant turnover of positions, many are only semiskilled jobs, and many new immigrants "take those kinds of jobs until they can acquire enough English language skills to get a better one."

But some minority businessmen note that food service employes are not covered by minimum wage laws; restaurants may be using the underemployment among ethnic groups to keep labor costs down, they say.

Developers are already playing up the Pike's new "international" population. "It's like Georgetown used to be," said former Rockville city designer David Chikvashvilli, himself a native of Soviet Georgia. "It plays off the reputation of the nation's capital" as an international center.

The Pike's current popularity and its attendant traffic crush raise the question: Will success spoil Rockville Pike?

Shopping strips that had evolved as convenience centers, such as Congressional Plaza, are giving way to "concept" malls such as White Flint, that offer every fashion instead of every necessity. Shoppers have to drive between strips; and what with the heavy traffic, even the old-fashioned malls aren't so convenient anymore.

"All-commercial development could drive people away," one transportation planner cautioned. "Too much of anything strangles itself."

One antidote, say county and city planners, is a greater residential population. With at least 30,000 persons already employed on the Pike, there is a growing demand for moderately priced housing, from which one can walk to work or mass transit.

But most new housing on the Pike is admittedly "luxury." At the Fallswood, two nouveau-Victorian brick towers looking down on White Flint from Nicholson Lane, one-bedroom condos start at $104,000. The Woodmont Overlook complex, near Woodmont Country Club, will total 88 town houses starting "in the mid-$150s," and eventually spin off a mid-rise condo project next door.

"Sure, I'm single, I work around here, I'd live around here" if there were apartments, said Diane Simms, who drives from Gaithersburg to her bartending job at the Crowne Plaza Hotel. "The biggest thing is, it would have to be affordable for the location. Around here, you have to make $17,000 to $18,000 to qualify for renting a one-bedroom."

Even officials at Metro, whose successful promotion of the Red Line subway is primarily responsible for the commercial building boom, favor more residential or combined development.

"Mixed use is our bag," according to Metro development director Dick Miller. "It creates a much better opportunity for two-way flow. If you have all office buildings, you suffer heavy traffic" all in one direction at the same time. "And it's better for the community, better for the infrastructure."

The transit authority is involved in mixed-use projects near White Flint and Grosvenor, not only to counteract what Miller calls "office sprawl," but to ease that most famous of Pike peeves, the traffic.

"The problem is, now you can't get from one side of the street to the other without getting killed," said former county planner John Westbrook. "But what if you had shuttle buses that circled between shopping malls and the neighborhoods? What if all the people who worked at White Flint could get there without a car? What if you could go back to having the cleaning picked up, or the milk delivered? You don't have to solve the whole traffic problem: All you have to do is solve 20 percent, and that would make a lot of difference."

"All it takes," said Chikvashvilli, "is vision and money."

And, Westbrook said with a grin: "If there's one place in the country that can afford to pay the price of building a perfect Rockville Pike, this is probably it."