The Venetian parents, who have not been named, say their son has a job but refuses to leave home and wants his clothes washed and his meals prepared.
It's the latest case to highlight the phenomenon of Italy's stay-at-home "bamboccioni" or mummy's boys, reports the Daily Telegraph.
The elderly couple say their son has a good job and a steady income but has resisted all attempts to persuade him to fly the nest.
They have taken their case to the legal department of an association for the defence of consumers' rights in Mestre, near Venice.
Lawyers have given the middle-aged man, also unnamed, 10 days to find himself a flat, or have the case referred to court, with the prospect of being evicted.
"We can no longer go on like this," the father said, according to Andrea Campi, a lawyer from the consumers association.
"My wife has developed stress-related problems and she's been in hospital recently.
"He has a good job but he continues to live at home and wants his clothes washed and ironed and his meals cooked for him. He never wants to leave."
Young Italians are renowned for their reluctance to leave home, with a study released last year showing that 48% of offspring between the ages of 18 and 39 still live under their parents' roofs.
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