Barnsley have beaten Nottingham Forest and Middlesbrough to reach this stage, but have lost their opening two Championship games of the season.
The side have not met since the South Yorkshire club stunned the west Londoners in the FA Cup in 2008, upsetting the odds to win 1-0 at Oakwell.
When is Chelsea vs Barnsley?
The match kicks-off at 7.45pm on Wednesday 23 September.
Is Chelsea vs Barnsley on TV and is there a live stream?
Streams of all matches on Wednesday are available on the Carabao Cup website.
Frank Lampard has revealed that Thiago Silva and Ben Chilwell will make their Chelsea debuts against the Tykes, while Callum Hudson-Odoi is also set to play on Wednesday.
Hakim Ziyech and Christian Pulisic are still not fit enough to make their first appearances of the season.
Chelsea vs Barnsley odds
Odds courtesy of Betfair