The grocery chain is also becoming a retailer with Amazon's Prime website and app, and will begin selling directly to customers, through Morrisons at Amazon.
Currently available to Amazon Prime Now customers in Leeds, Manchester, Birmingham, and parts of London and the home counties, the same-day online grocery shopping service will now be extended to cities including Glasgow, Newcastle, Liverpool, Sheffield and Portsmouth.
But Morrisons will continue as a wholesaler for all Amazon's other UK grocery offers for customers.
David Potts, chief executive at Morrisons, said: "Morrisons' conveniently located local supermarkets and Amazon's very popular website and customer offer are an ideal combination, offering ultra-fast same-day grocery home delivery for customers in and around cities across Britain.
"Amazon has been a valued partner of Morrisons for over three years and we are pleased to be expanding our relationship together."
Doug Gurr, Amazon UK country manager, said: "We have greatly valued our relationship with Morrisons since the launch of the Morrisons store on Prime Now in the UK in 2016 and expanding this relationship enables us to offer Morrisons' high-quality grocery selection to even more Prime members.
"We are committed to growing our grocery business so that we can continue to deliver what we know our customers will always care about - low prices, vast selection, and fast delivery - and our relationship with Morrisons is an important part of that long-term growth.
"With the Morrisons store on Prime Now, many Prime members can do their full weekly grocery shop online through Prime Now with ultra-fast same day delivery."