The offer included a portion of Twenty-First Century Fox's non-voting common stock and $32.42 in cash for each Time Warner share, Time Warner said. At Tuesday's closing prices, that is worth about $86.30 per Time Warner share, a 22 percent premium.
Time Warner said Wednesday that its board rejected the bid after determining that its own strategic plan was better for the company and its stockholders and "is superior to any proposal that Twenty-First Century Fox is in a position to offer."
The New York company also said a combination with Twenty-First Century Fox carried considerable strategic, operational and regulatory risks. It said there was uncertainty in the valuation of Twenty-First Century Fox's non-voting stock and in the company's ability to handle a combination of this scale.
Twenty-First Century Fox confirmed in a short, separate statement that Time Warner had rejected its bid, but it did not provide any details. It added that it is not currently in discussions with Time Warner.
But the New York Times, citing unidentified people, said that Murdoch is determined to make a deal.
Time Warner Inc.'s holdings include the cable movie channel HBO and Warner Bros. studios. It spun off Time Warner Cable into a separate company in 2009 and last month separated from its publishing division Time Inc. to focus on its faster-growing TV and movie business.
Murdoch's News Corp. also split into two companies, last year: The newspaper and publishing portion, still called News Corp., and the more profitable film-and-TV unit, Twenty-First Century Fox Inc.
Shares of Time Warner rose 17 percent, or $12, to $83.01 in late morning trading, while Twenty-First Century Fox fell 2.9 percent, or $1.02, to $34.17.