Martin Lefley, of Northwest Driveways, spotted a silver glint among piles of concrete in a trailer at the Wyre Waste Management depot in the town.
Both caskets were engraved with names, the larger one inscribed with 'William Dewhurst, who died June 21 1994, age 82'.
And the smaller casket just has the name 'Walter Grant'.
How they ended up in the trailer is still a mystery, but the find even shook up Martin, who is used to unearthing all kinds of objects in his work.
Now he hopes both caskets can be returned to their families.
He said: "It's a bit gruesome really - I'm not usually phased by much, but this gave me goosebumps
"I spotted the plaques as I emptied the trailer and when I looked more closely, I realised what they were."
"They were in a large trailer load of rubble and I'm unsure whether they had come from my trailer or whether they were there before."
He added: "Whether we dug them up on a previous job, or whether they were at the waste site before I got there, I don't know.
"But I know they need to be returned to the families."
At Wyre Waste, site manager Phil Leadbetter said he had been told of the find but had not yet spoken to Martin personally.
Martin has been in touch with Fleetwood funeral director Jason Dell, based on Poulton Road, who has made local enquiries but so far drawn a blank.
Mr Dell, of the firm JP Dell, said: "We will keep the caskets here for six months and if no one claims them after that we will scatter the ashes over the garden of remembrance at Carleton Crematorium."