It seems the black moggy - known as One-Eyed Jack - had been living on his wits since going missing from Dion Mellor-Senior's house in Plymouth.
Jack had spent the past 17 months living in a vent at a local college.
He was eventually coaxed out and taken to a pets' home. It placed a newspaper ad in a bid to find the cat's owners and a shocked Dion came forward.
"We didn't think it could be our cat, but when we saw him it was exactly the same one," said Dion.
"It was quite an emotional reunion. He was really affectionate and friendly.
"It is really nice to have him back."