The Seagulls drew 0-0 with Championship side West Brom at the Amex on Saturday and the replay will take place next week, with an exact date still to be confirmed.
The match with Frank Lampard's Derby will take place between February 15 to 18.
Only five Premier League clubs are definitely in the last 16 - Manchester City, Chelsea, Manchester United, Watford and Crystal Palace.
Brighton and Wolves are the only other Premier League clubs still in the competition. The Seagulls have their replay at the Hawthorns, while Wolves will host League One Shrewsbury in their replay after a 2-2 draw on Saturday.
The full draw is: Bristol City v Shrewsbury Town or Wolverhampton Wanderers
AFC Wimbledon v Millwall
Doncaster Rovers v Crystal Palace
Middlesbrough or Newport County v Manchester City
Chelsea v Manchester United
Swansea v Barnet or Brentford
Portsmouth or Queens Park Rangers v Watford
Brighton & Hove Albion or West Bromwich Albion or Derby County
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