The agreement will generate around £4m next season if all goes well. That amount could rise as the deal progresses.
Unlike any previous arrangements, Leeds will deal directly with the supplier and have the bonus of being able to sell to selected retail outlets.
Glasgow Rangers have a similar deal in place with Diadora and are generating almost £9m a year. United managing director David Richmond is delighted with the deal and the freedom it gives the club.
Richmond said today in the YEP: "The aim within two years is for the retail division of the club to generate £4m a year. This deal will underpin the growth of profit in retail.
"It will give us control of our own branding and merchandising and, in the longer term, will cut out the middle man.
"It will give the supporters good value and quality."
An official launch will take place in June when the new kits will be available.