Cotton Traders is spending£1 million to overhaul the business applications in its retail and mail-order chains.
MySAP is providing technology for customer relationship management, supply chain management, procurement, finance and distribution.
Cotton Traders managing director Fran Cotton said the project would radically change the way his company works.
He said: 'This will give us operational excellence. The aim is to offer next-day delivery to everyone who orders before 2.00pm - at the moment it takes three to four days to deliver the orders.
'We will also be much more efficient and there will be significant operational cost benefits. There will be less stock and much lower costs for dispatching orders.'
Cotton said the retailer had a shortlist of four or five suppliers, but SAP was ahead of the rest. He said: 'We do retail, wholesale and mail order, and SAP was the only fully integrated solution for all three areas.'
The company had bolted systems onto each other as the business had grown, and the move to one integrated system should make life easier, said Cotton.
SAP will also give a more transparent supply chain.
Cotton said: 'We will be able to give our main suppliers access to the same information we have.'
Of the retail side, he said: 'This will improve the speed of replenishment in stores. At the moment, sales analysis takes ages. The new system will make that easier - it will give us real-time access to sales.'
Cotton Traders is working with SAP reseller Chelford SAP Solutions to get the project up and running. The software will run on H-P hardware.