Defenders of Mexican culture see the chain's re-entry as a crowning insult to a society already overrun by U.S. chains from Starbucks and Subway to KFC.
"It's like bringing ice to the Arctic," pop culture historian Carlos Monsivais said.
The company's branding strategy - "Taco Bell is something else" - is an attempt to distance itself from any comparison to Mexico's beloved taquerias, which sell traditional corn tortillas stuffed with an endless variety of fillings, from spicy beef to corn fungus and cow eyes.
Taco Bell, a unit of Kentucky-based Yum Brands Inc., made its name promoting its menu to Americans as something straight out of Mexico. But it's a very different dynamic south of the border.
Here, the company is projecting a more "American" fast-food image by adding french fries - some topped with cheese, ground meat and tomatoes - to the menu at its first store, which opened in late September in the northern city of Monterrey.
Other than the fries and sales of soft-serve ice cream, "our menu comes almost directly from the U.S. menu," said Yum Mexico Managing Director Steven Pepper.
Some of the names have been changed to protect the sacred: the hard-shelled items sold as "tacos" in the U.S. have been renamed "tacostadas." This made-up word is a play on "tostada," which for Mexicans is a hard, fried disk of cornmeal that is always served flat, with toppings.
Although Mexicans eagerly buy many American brands, the taco holds a place of honor in the national cuisine. Mexicans eat them everywhere, any time of day, buying them from basket-toting street vendors in the morning or slathering them in salsa at brightly lighted taquerias to wrap up a night on the town.
Taco Bell has taken pains to say that it's not trying to masquerade as a Mexican tradition.
"One look alone is enough to tell that Taco Bell is not a 'taqueria,'" the company said in a half-page newspaper ad. "It is a new fast-food alternative that does not pretend to be Mexican food."
It's still a mixed message for Mexicans such as Marco Fragoso, a 39-year-old office worker sitting down for lunch at a traditional taqueria in Mexico City, because the U.S. chain uses traditional Mexican names for its burritos, gorditas, and chalupas.
"They're not tacos," Mr. Fragoso said. "They're folded tostadas. They're very ugly."
Taco Bell failed with a highly publicized launch in Mexico City in 1992, when it opened a few outlets next to KFCs. Now, both KFC and Pizza Hut are owned by Yum Brands.
Mexicans were less familiar with foreign chains back then, and the economy was on the verge of a crisis. The North American Free Trade Agreement had yet to be signed. The restaurants didn't even last two years.
Since then, free trade and growing migration have made U.S. brands ubiquitous in Mexico, influencing everything from how people dress to how they talk.
McDonald's has modified its menu to offer eggs "a la Mexicana" and even hands out packets of jalapeo sauce with its hamburgers. In contrast, Taco Bell advises customers of offerings that are "spicy" instead of the Spanish "picante."
"Taco Bell wants to take advantage of the perception that if something comes from the United States, it tastes better, that a country that has been Americanized is willing to Americanize food that is central to its cuisine," Mr. Monsivais said. "It is an absurd idea, and given that it's so absurd, it may just be successful in upper-class areas."
With U.S. sales sluggish, Yum Brands has been expanding abroad. Its goal is to have 800 stores in its international division by the end of this year.
Yum Brands reported recently that third-quarter profits rose 21 percent in its international division and 28 percent in China, while U.S. profits rose a scant 1 percent. Same-store sales at company-owned Taco Bells fell 6 percent for the three months that ended Sept. 8.
In Mexico, U.S. chains such as KFC and Chili's Grill & Bar have been wildly popular, but one of the most successful has been Starbucks, which opened more than 150 stores in five years, although its venti chai latte costs almost as much as a day's minimum wage.
The Starbucks are mainly in wealthier neighborhoods. Taco Bell is aiming at a different demographic - opening in the middle-class Monterrey suburb of Apodaca, where residents might not have traveled to the U.S.