The game will be played at St. James' Park on Saturday, 25th January with a 3pm (GMT) kick-off. It has not been selected for live television broadcast.
Ticket news will be announced on Wednesday. Goals from Miguel Almirón, Matty Longstaff, Joelinton and an own goal from Eoghan O'Connell saw United progress following a 1-1 draw at Rochdale ten days earlier.
Newcastle's only previous meeting with Oxford in the FA Cup also came at the fourth round stage stage, in 2016/17, with the U's winning 3-0 at the Kassam Stadium.
The two sides have met 18 times in all competitions, with Oxford winning seven, Newcastle six and five games ending in a draw.
Oxford beat Hartlepool United 4-1 in the third round and have also seen off Walsall (1-0) and Hayes & Yeading United (2-0).
Managed by Karl Robinson, they sit fifth in League One and reached the quarter-finals of this season's Carabao Cup, where they lost 3-1 to holders Manchester City.