The second round tie, which will be played in the week commencing August 24, will be the first time the Whites have faced Watford since the playoff final in 2006, when the Hornets secured their place in the Premier League with a 3-0 win.
Full draw for the second round of the Carling Cup (ties to be played week commencing August 24):
West Brom v Rotherham
Norwich v Sunderland
Tranmere v Bolton
QPR v Accrington
Bristol City v Carlisle
Leyton Orient v Stoke
Port Vale v Sheffield Wednesday
Hull v Southend
Leeds v Watford
Cardiff v Bristol Rovers
Portsmouth v Hereford
Crystal Palace v Manchester City
Wolves v Swindon
Gillingham v Blackburn
Blackpool v Wigan
Southampton v Birmingham
Preston v Leicester
Newcastle v Huddersfield
West Ham v Millwall
Coventry or Hartlepool v Burnley
Nottingham Forest v Middlesbrough
Reading v Barnsley
Swansea v Scunthorpe
Doncaster v Tottenham
Peterborough v Ipswich