The lowest ranked team left in this season’s competition, Cambridge United, will host Louis van Gaal’s men in a match which will more than likely be covered live for television.
Chelsea could face a London derby with Millwall if they can get past a replay at League One side Bradford and cup holders Arsenal face a tricky away trip to Championship outfit Brighton.
Premier League champions Manchester City will be at home again to Championship opposition with Middlesbrough the visitors this time.
Fourth-round of draw: Southampton/Ipswich v Crystal Palace, Cambridge United v Manchester United, Blackburn v Swansea, Chelsea v Millwall/Bradford, Derby v Scunthorpe/Chesterfield, Preston v Sheffield United, Birmingham v West Brom, Aston Villa v Bournemouth, Cardiff v Reading, AFC Wimbledon/Liverpool v Bolton, Burnley/Tottenham v Leicester, Brighton v Arsenal, Rochdale v Stoke, Sunderland v Fulham/Wolves, Doncaster/Bristol City v Everton/West Ham, Manchester City v Middlesbrough.
Ties to be played across the weekend beginning January 24.