Technology news website Re/code, which reported news of the deal earlier, said the price was $400 million, without disclosing where it got the information.
A Google spokesman declined to comment on the price. DeepMind representatives could not be immediately reached for comment.
Founded in London in 2012 by Demis Hassabis, Shane Legg and Mustafa Suleyman, DeepMind uses general-purpose learning algorithms for applications such as simulations, e-commerce and games, according to its website.
Google, which is working on projects including self-driving cars and robots, has become increasingly focused on artificial intelligence in recent years.
In 2012, it hired Ray Kurzweil, considered one of the leading minds in the field, and in May it announced a partnership with NASA and several universities to launch the Quantum Artificial Intelligence Lab.
Google in December also announced the acquisition of Boston Dynamics, military contractor that has raised intrigue by releasing videos of its inventions in recent years. Those inventions include a four-legged robot capable of galloping past Olympian sprinters and a jumping contraption that can leap onto tall buildings. Another video of a creepy-looking four-footed machine has been watched more than 15 million times since it was posted on Google's YouTube site five years ago.
Besides designing animal-like robots, Boston Dynamics also has been working on humanoids as part of a $10.8 million contract with the U.S. government's Defense Advanced Research Projects Agency, or DARPA.
Founded in 1992 by former Massachusetts Institute of Technology professor Marc Raibert, Boston Dynamics says it is dedicating to "changing your idea of what robots can do."Google has in the recent past purchased eight companies that specialize in robotics this year. The acquisitions are being assembled into a new robotics division headed by Andy Rubin, who oversaw Google's development of Android, now the world's leading mobile operating system.