The Serie A club was willing to negotiate a sale after the Red Devils made overtures but coach Rudi Garcia confirms that the midfielder is set to stay for the season
The Premier League champions indicated this week to Roma that they were willing to pay £10 million for the experienced Italy international.
Goal has learned that the Serie A club was willing to negotiate De Rossi's sale after lining up Cagliari midfielder Radja Nainggolan as a replacement but, after lengthy consideration, the Giallorossi star has turned down the opportunity to join David Moyes's team.
"De Rossi is a Roma legend and wants to play for Roma," coach Rudi Garcia told the press of the midfielder's decision. "We said that, after a certain point in the summer, he'd no longer be for sale [and] he is a man of his word. That date has passed and he will be with us for the entire season."
The 30-year-old has been assured by Garcia that he will have more first-team chances after slipping down the pecking order at Roma last season.
Nevertheless, influential sporting director Walter Sabatini would have recommended selling De Rossi in order to recruit Nainggolan.
It is another blow for United as it attempts to reinforce its midfield before Monday's deadline.
Moyes has already failed in bids to land Spanish pair Cesc Fabregas and Thiago before having offers rejected for Marouane Fellaini and Athletic Bilbao's Ander Herrera.
United is expected to table improved offers for Fellaini and Herrera after missing out on De Rossi.