Financial terms of the deal to buy Scout deal were not disclosed, but the newly acquired business will become part of Fox Interactive Media.
Scout Media's network of sports websites include 200 local sites and 47 publications that cover professional, college and high school sports teams in the US. The privately owned company claims to have 200,000 subscribers and 2.4m unique users a month.
The purchase is part of a rapid acquisitions binge that saw News Corp snap up the fifth most popular portal in terms of page views in the US when it took over Myspace.com.
Also in the pipeline is News Corp's £52m takeover bid for online property listings site Realestate.com.au.
News Corp has been widely expected to expand its online interests since February, when Murdoch gathered his top executives in New York to discuss how to react to the internet's rising popularity.
"The threat of losing print advertising dollars to online media is very real, in fact, it's already happening, particularly in classifieds," Murdoch said in a speech to newspaper editors in April.
Last month, News Corp announced the formation of Fox Interactive Media, a new unit that will develop Fox's entertainment, news and sports brands across the web to offer a richer online experience.
Fox Interactive Media also oversees News Corp's sports channel websites including Fox College Sports, Fox Sports Net's 20 and Speed.
Scout was formed by former National Football League player Bernie Kosar in 2001.
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