Two kittens were rescued from among vegetable peelings and grass cuttings in a compost bin moments before the contents were due to be compacted.
Binmen were sorting through rubbish for items that could not be composted when they found the kittens at a composting facility near Bury St Edmunds, Suffolk.
A spokesman for St Edmundsbury Borough Council said the animals would have died if they had not been spotted.
One kitten escaped but the other was given a home by a member of staff.
Staff know the bin was picked up somewhere in the St Edmundsbury or Forest Heath areas of the county, but have been unable to narrow it down any further.
Both black and white kittens were about 12 weeks old.