The Federal Trade Commission has approved the merger between US heavyweights America Online and Time Warner.
A unanimous vote gave the green light to a combined company with media and internet interests worth £87 billion.
However, the FTC did impose a number of conditions, primarily to protect open competition in broadband technology.
AOL/Time Warner will now have to provide access to its cable systems – which connect 20% of US households – to at least three other ISPs. The FTC will also have the right to approve some contract conditions with ISPs.