City will play the first leg at Old Trafford.
The draw for the semi-final was held immediately after the game had ended at the Kassam Stadium.
Dates/time to be confirmed soon.
City and United have met seven times in the League Cup over the years and this will be the third time the Manchester giants have faced off in the semi-final.
The final will be held at Wembley on Sunday 1 March 2020.
Thoughts on the draw?