The deal has been beset by delays, including an eleventh-hour bid by a Chinese consortium which nearly scuppered Marriott's bid altogether, and a 60-day delay imposed by the Chinese ministry of commerce.
Starwood shareholders will receive $21 in cash and 0.8 shares of Marriott International for each share they own, while shares in the company will cease trading on the New York Stock Exchange before the market opens today.
The new company will operate or franchise more than 5,700 properties in 110 countries with 30 brands, ranging from Sheraton to Ritz-Carlton, Meridien Renaissance and the ultra-trendy, nightclub-style W Hotels.
"Throughout our nearly 90-year history we have never stopped searching for innovative ways to serve our guests," said JW Marriott Jr, the company's executive chairman.
"With the addition of Starwood’s strong brands, great properties, and talented people, we have dramatically expanded our ability to provide the best experiences to our customers."