The Argentina-born Bayala, who is one of South America's most acclaimed creative directors, will rejoin Mother to work on the launch of its brand in South America.
Initially, Bayala will divide his time between Mother's London operation and investigating the potential for launching a Mother presence in Buenos Aires.
The agency, which opened its New York venture only last year, hopes to establish a presence in the region as early as 2005.
Once he has selected a team to run the South American office, Bayala will relocate there to take up a central role in the operation.
Bayala said: "It is very sad to leave W&K. It is such an amazing agency with so many wonderful people. However, I wouldn't turn my back on such an amazing opportunity. The Mother brand and family are very special."
Bayala has spent the past year running W&K Amsterdam's creative department after moving from the agency's Portland office, where he was the creative director for its Latin American division.
Before first joining Mother in 1999, he spent three years heading Graffiti DMB&B and was the creative director at Young & Rubicam in Buenos Aires between 1992 and 1996.
He returns to Mother with his wife and creative partner, Gabriella Bayala.
Among the pair's international creative accolades are five Lions at Cannes, two gold Clios and a gold in the One Show for the lubricant Tulipan, which featured an elephant and an ant in a bed. The pair also won a D&AD Pencil in 1995 for their ad for the mosquito repellent Shelltox.
During his previous spell at Mother, Bayala worked on Coca-Cola, Super Noodles and Kiss FM and created much of the work for the launch of Coke's Alive brand.
Most recently, he was also among the creative directors behind the Nike "home game" campaign, which is on air at present.
The Mother founder Robert Saville said: "Carlos is massively respected and is one of the most talented creative people I have worked with. It's always nice when someone new joins Mother, but it is twice as rewarding when people return.
"It could take a year or two, but we are keen to set up in Latin America, where there are a lot of talented people. Carlos is known by all of them, and will give us the opportunity to bring some of them into the Mother family."