The game with The Us will take place at Selhurst Park in the week commencing 26th August, with tickets going on sale from 5pm tomorrow (Wednesday 14th August).
Last year in the competition, Palace overcame Swansea City in the second round, defeating the Welsh club 1-0 at the Liberty Stadium.
The Eagles and Colchester last faced off in 2008, the south Londoners winning 2-1 in SE25.