Having seen off Brighton, Reading and Liverpool in last season's competition, Northampton will face Ipswich Town, the team who eventually knocked them out of the League Cup, in the opening round of the 2011/12 tournament.
The tie will take place at Portman Road in the week commencing 8 August.
The Cobblers have finalised their pre-season plans with the announcement of two more friendly fixtures, including an attractive home game against Nottingham Forest, now managed by former England boss Steve McClaren, on Wednesday, July 20.
A trip to face Cambridge United is in the diary for Tuesday, July 26. Northampton will also face Reading and Wycombe Wanderers at Sixfields.
Freed defender Dean Beckwith has joined Luton Town while Northampton boss Gary Johnson has said he is relaxed about the goalkeeping situation at the club should Chris Dunn move on this summer.
He told the Chronicle & Echo: “We’ve got options and the more likely outcome is that we bring in a very good young one that is a very good goalkeeper.
“There’s enough keepers out there that are available."