Staff at Jossals, in Queen Street, revealed last week that the business is now up for sale.
The business is owned by Sally Graham, Jo Parsons, Nick and Maxine Guymer.
In a letter sent out last week, they told customers: “We have thought long and hard about our future and no-one has a crystal ball and knows what it may hold.
“We are all starting to wear out with this hard industry and know that at some stage in the future we look forward to retirement but that is a few years away yet.
“We do not want to get to the situation where we have to sell the business because of situations beyond our control, such as health or family issues, so we thought now is the time to dip our toe in the water and see if anyone out there might like to take over this wonderful institution.
“We will continue to operate totally as we do now so do not worry you will still continue to get wonderful food & service just as you have been doing over the last 30 years.”
It was also stressed it will not be a quick sale.
They added: “Market Rasen has served us well and we have seen many changes, some good, and some not so good, over the years.
“We are in no rush to sell and it may take years before we find a suitable buyer and by then we will be ready to retire.
“In the meantime, we would like to take this opportunity of thanking all of our staff and customers for their continued support.”
Rasen mayor, Coun John Matthews emphasised the role Jossals has played in the town.
Coun Matthews said: “They have been a significant part of the High Street for many years.
“I remember when they were at the other end in smaller premises and the leap of faith they undertook to move in to the Old Post Office, but they have worked hard and made Jossals the success it is today. I hope that they find a buyer who wants to continue the business and personally wish them well for the future.”