Value chain Peacocks has chosen JDA to supply EPoS and store management systems for its 370 stores.
No official value for the contract has been given, but the figure is thought to be more than£5 million.
The 270 Bonmarche stores acquired by the group in July last year will not be included in the refit.
The project, headed by Peacocks project manager Liz Sayce, will involve replacing the retailer's full front- and back-office systems, including solutions previously provided by NSB and an in-house merchandise management application.
The new system will handle the centralised distribution of information - such as pricing and promotional data - direct to central store PCs.
Sayce said: 'We have had 17 stores refitted so far, but we are not able to tell what the impact will be. It's still too early to tell in monetary terms.'
The retailer has committed to an expansion of the estate and all new stores will be fitted with the solution.
The first phase involves 30 to 40 stores, which will be refitted by the end of September. The retailer will then review the time plan for the remainder of the estate.