The 51-year-old Roeder was given a two-year contract in May 2006 after coaching the club on a caretaker basis after Graeme Souness had been fired three months before.
Roeder left after meeting with the board late Sunday, according to Sky Sports News and Britain's Press Association.
Sam Allardyce was reportedly the favorite to take over. Allardyce quit as manager of Bolton last Sunday.
Newcastle lost to Blackburn 2-0 in the Premier League on Saturday, and fans jeered the players off the field. Saturday's game extended Newcastle's goal drought at St. James' Park to five games, the club's worst run since 1951.
Roeder has had to deal with several injuries this season, notably striker Michael Owen, who made his comeback from a serious knee injury two matches ago.
Newcastle is 13th in the league and plays its final game of the season at Watford next Sunday.
Roeder has also managed West Ham, Watford and Gillingham.
Russia has been developing an energy module on the basis of the megawatt-class nuclear power plant since 2010. The spaceship needs neither sunlight nor solar batteries
There are legitimate authorities in Donetsk and Luhansk republics now, with which Russia can implement the project of the economic integration of the Donbass
Austria does not intend to expel Russian diplomats because of the spy scandal