The fast-food giant launched McSomtam in a 10 million baht (US$230,000) television and print campaign, and will follow this with the introduction of grilled pork (moo yang) and sticky rice (khao nieow) dishes.
"The addition of McSomtam to the menu is very much in line with our policy within the region to encourage all McDonald's restaurants to offer foods that satisfy local taste,
said Dej Bulsuk, president of McThai.
McDonald's first Thai-style dish, the hot basil pork (krapao) burger, was introduced in 1998.
That was followed by the panang chicken burger in 1999 and the satay chicken burger in 2001.
However, the latest campaign demonstrated a deepening of the localisation approach that formerly focused just on the burger, and had used bread instead of rice.
Leo Burnett Thailand handles the McDonald's account in Thailand.
"The concept is to go into the culture rather than forcing the culture, and offer the food that customers want to find,
said the agency's general manager, Sasie Vadhanapanich.
"It is not copying the original dish. It is almost fusion food - but there's a feeling of familiarity.
"The purpose is to get the attention of people and convey the message that McDonald's is a company that listens to its customers and is trying to get closer to them."
The television commercial features up-and-coming soap star, Pornchita Na Songkla, who dances with a somtam shaker to the beat of traditional Thai music.
"We picked a celebrity as it gets the attention of the mass market. She is also very lively and approachable,
added Sasie.
"This is the image we want to project - that McDonald's is not just a Western eating place, but somewhere where you can find what you want and it is fun,
she added.
The move by the American fast food giant mirrored similar initiatives in other regional markets, such as the Philippines, Indonesia, Malaysia and India, where rice is now featured on menus.
"A lot of brands are trying to open up to local tastes and McDonald's Thailand is moving in that direction too.
"They are trying to offer more of good eating out experience and a place where a family can have a full meal."
