Families of 52 elderly residents at two care homes have said they are upset and disgusted that they are to close.
Clyde House and Leolyn care homes in St Leonards, East Sussex, are the second and third homes in the town to be shut by New Century Care within a year.
The company has blamed the national funding climate, saying it has "a moral and regulatory duty to make sure our homes are financially sustainable".
East Sussex County Council said it would explore potential alternatives.
Colin Paige-Mitchell's 88-year-old mother, Marjorie, has dementia and is facing her second home in the space of a year after being moved from St Paul's, in St Leonards, to Clyde House when it was closed by the same company last March.
He said: "We had a residents' meeting after Christmas and we said how wonderful the home is... and then a week later we get a [closure] letter saying exactly the same as last year."
Mr Paige-Mitchell added: "We've already been turned away by two homes that we thought we could put her into because they couldn't meet her needs."
New Century Care said its "absolute priority" was the health, well-being and safety of residents.
Linda Astell, who used to be a manager with the company, said "the government needs to put more money into social care".
Challenged about social care funding on The Andrew Marr Show on Sunday, the prime minister said she recognised there were pressures but said more money was being made available.
"This is an issue that's been ducked by governments for too long," Theresa May said.
"That's why I have set up work to say we need to find a solution so that we've got a long-term sustainability of our social care provision."