The internet retailer has forked out $970m (£585m) for Twitch - a similar sum that Google had been reported as willing to pay - and It's now expected that Amazon's acquisition will be completed during the final quarter of the year.
Twitch was founded in 2011 with an exclusive focus on live video for gamers, with more than 55 million unique visitors arriving at the site last month to view more than 15 billion minutes of content produced by over one million gamers and more.
Amazon founder and CEO Jeff Bezos said: "Broadcasting and watching gameplay is a global phenomenon and Twitch has built a platform that brings together tens of millions of people who watch billions of minutes of games each month."
Twitch CEO Emmett Shear added: "We will be able to create tools and services faster than we could have independently. This change will mean great things for our community, and will let us bring Twitch to even more people around the world."