Plans for a 60,000 sq ft Sainsbury's foodstore in Meols Cop Retail Park have been approved by Sefton Council.
The store will offer customers Sainsbury's full food range, as well as the Tu clothing range.
The plans include revised car parking, a petrol filling station and improved pedestrian access and landscaping. The store would also feature a customer café serving hot and cold food.
The application was put forward jointly between Sainsbury's and UBS, the owner of the site.
As part of a consultation programme, the proposals were unveiled at a public exhibition in March, and gained support from members of the public, with more than 84% of respondents in support of Sainsbury's plans.
Andrew Sanderson, regional development manager for Sainsbury's, said: "The new foodstore will increase choice and create 400 jobs once open as well as hundreds more throughout the construction phase, providing a significant boost to the local economy. With great support from a large number of local residents, we would like to thank all our supporters who have made this possible and we will keep local residents up to date as the project progresses."