Nisa shareholders have approved the symbol group’s £137m takeover by the Co-op.
At an emergency meeting, the takeover won 75.79% of shareholders’ votes. It needed the support of 75% of shareholders.
With more than 3,000 stores and a wholesale business, Nisa is a member-owned group.
The board said the deal was in the “best interests” of members.
Nisa chairman Peter Hartley said: “The convenience store environment is changing rapidly, and is unrecognisable from that which existed when Nisa was founded more than 40 years ago.
“Co-op will add buying power and product range to our offering, while respecting our culture of independence.”
The deal gives Nisa members the choice to not buy goods through the Co-op.
Due to changing shopping patterns, strong competition from the discounters such as Aldi and Lidl, and the growth of Amazon, retailers including the Co-op have been trying to bolster their businesses by buying food wholesalers.
Tesco’s proposed £3.7bn takeover of Booker is subject to a competition inquiry.
Nisa’s nearly 1,200 members, who own 3,400 stores, are dealing with increased competition, rising rents, declining tobacco sales and food inflation.