The duo (photographed in 2008) founded Google 21 years ago
Larry Page and Sergey Brin, co-founders of Google, announced they are leaving the giant's parent company online.
The pair will leave their respective roles as CEO and President of Alphabet, but will remain on the board of the company.
Google CEO Sundar Pichai will also become CEO of Alphabet, a statement said.
Alphabet was created in 2015 as part of a corporate restructuring of Google, which Page and Brin founded in a California garage in 1998.
The parent company intended to make the technology giant's activities "cleaner and more responsible" as it expanded from Internet search to other areas such as autonomous cars.
The pair switched from Google to Alphabet when they were formed – saying they were making the leap to focus on starting new initiatives.
But in a post on Tuesday, the couple, both 46, announced their departure from the alphabet.
A joint letter said they would remain "actively involved as board members, shareholders and co-founders," but said it was "the natural time to simplify our management structure."
"We have never been the ones who retained management roles when we thought there is a better way to run the business. And Alphabet and Google no longer need two CEOs and a president," the letter says.
They also stated that it was time to "take on the role of proud parents – offering advice and love but not bothering them daily" and insisted that "there was no better person" to lead the company in the future than Pichai.
The 47-year-old man was born in India, where he studied engineering. He studied in the U.S. at Stanford University and the University of Pennsylvania before joining Google in 2004.
Sundar Pichai will now serve as CEO of both companies.
In a statement, he said he was "excited" about the transition and paid tribute to Page and Brin.
"The founders gave us an incredible chance to impact the world," said Pichai. "Thanks to them, we have a timeless mission, enduring values and a culture of collaboration and exploration that makes working every day exciting.
- Google's new boss from humble roots
"It's a solid foundation on which we will continue to build. I can't wait to see where we are going next and look forward to continuing the journey with you all."
& # 39; Proud Parents & # 39; who are not giving up the supreme power
This move represents the most significant leadership change at Google since its inception – the first time that the dynamic pair of Brin and Page, a legendary Silicon Valley partnership, will have no major management roles in the company it founded.
In reality, however, this has been the case for some time – the company's public face has been Pichai and, to a lesser extent, YouTube chief executive Susan Wojcicki. But Tuesday's announcement makes it absolutely clear: Page and Brin are not running the company.
However, while the pair is apparently renouncing management functions, this does not mean giving up supreme power. Among them, they control 51% of the voting rights on Alphabet's board. That will not change. They compared their new role to being "proud parents" of the company, watching with great interest and care.
But if they feel the need, they can overturn any decision made by Pichai – with little more than one parent "because we said that."
Page and Brin are the 10th and 14th richest individuals in the world by Forbes, with each estimated at about $ 50 billion.
American Business Magazine Ranks Alphabet 17th Largest Public Company in the World, with an estimated market value of $ 863 billion.