The exhibition includes products from the company's Wrong for Hay collaboration with British designer Sebastian Wrong. The hundreds of Hay products on show range from furniture to textiles, glassware, stationary and lighting.
The mini market allows visitors to browse and purchase from the two aisles of wall-to-wall accessories.
Products from Sebastian Wrong include his Slope Chair, which has a moulded polyurethane foam seat and a solid ash or oak legs. The seat comes in black, grey or green and the legs come in natural ash, black stained ash or oiled oak.
"The Hay Mini Market was created as part of our Milan exhibition so that visitors would have access to Hay and Wrong for Hay's collection of small accessories," Wrong told Dezeen.
"It's been enormously successful, partly because, as is Hay's ethos, everything is reasonably priced so everybody can buy a nice product to carry away with them."
The exhibition is on show in the Via Ciovassino 3A for the Salone del Mobile in Milan from 8 - 13 April.