The supermarket chain initially forecast up to 2,600 redundancies, but it has since halved that number after a 45-day consultation with staff.
The Walmart-owned retailer, which has 578 stores across the country, also confirmed it would be creating 5,760 new roles, but the majority of these will be on a lower pay grade.
The plans affect about 4,100 managers.
Asda chief executive Andy Clarke said: "As much as it is my job, and privilege, to be CEO of this business and to do what is right for Asda as a whole, this is one of the most difficult decisions I've had to make.
"While I genuinely believe that it is the right decision for the future of Asda, knowing that it will result in valued colleagues leaving us is not easy."
Managers affected by the plans will either start training for their new jobs or take a redundancy package over the next few weeks.