The web giants have joined forces with AOL, Yahoo, Twitter and eBay to campaign against the Stop Online Piracy Act (SOPA), which they claim could be harmful to the internet, BBC News reports.
The legislation, backed by the creative industries, aims to give service providers new powers to tackle offending websites. The US House of Representatives will deliberate over the bill today.
"Unfortunately, the bills as drafted would expose law-abiding US internet and technology companies to new uncertain liabilities, private rights of action, and technology mandates that would require monitoring of websites," the web firms wrote in a letter addressed to the house.
"We are concerned that these measures pose a serious risk to our industry's continued track record of innovation and job creation, as well as to our nation's cybersecurity."
In the UK, the Motion Picture Association won a lawsuit forcing BT to take action against filesharing website Newzbin 2. The studio is now campaigning to coerce other service providers to do the same.
Similar measures to the SOPA could be implemented with the UK's upcoming Communications Act, which is currently under debate.
Opponents of SOPA have joined together to found Censorship US day to coincide with the legislation's debate. On the movement's official website, critics of the bill warn that it will hand the creative industries too much power over legitimate websites, as well of those in violation of copyright laws.