The television and radio giant, which last year paid £140m for music recommendation site Last.fm, has set up an office in Silicon Valley in an attempt to work more closely with the digital media industry.
In an interview with the Financial Times, Joshua Chaffin, the new head of CBS's digital division, said the company was on the acquisitions trail in response to worsening conditions in its traditional television and radio businesses.
He said: "I really do believe it's about survival... Every media company is gunning for properties in this space [digital media]."
The CBS digital team has met 387 US new-media companies in the past year and has bought minority stakes in around 12 of them.
In May last year, the broadcaster bought London-based music website Last.fm, making its founder Martin Stiksel a millionaire five years after the site's launch.
CBS is the largest commercial radio group in the US, with almost 200 stations. It is a major player in television and outdoor advertising, and also owns children's publisher Simon & Schuster.
In its 2007 end-of-year results, the group posted a 2% year-on-year decline in revenues to $14.32bn. Radio was the worst-affected area, down 11%.
CBS is not the only US media group on the acquisition trail. NBC Universal was yesterday reported to be close to finalising a deal to buy a stake in SCi Entertainment, the UK video games company that owns the rights to 'Lara Croft Tomb Raider'.