People shopping at Co-op will be able to carry their items home and then re-use the bags as bin-liners in their food waste caddy.
The bags, which cost 6p, are available from Co-op stores in Grays, Socketts Heath, Stanford Le Hope, Corringham and Aveley.
Danny Howarth, Co-op regional manager, said: “Every compostable carrier bag used is one less conventional plastic shopping bag in circulation. We believe they will have a significant impact upon the number of plastic bags which end up in landfill sites every year.
“Our compostable carrier bags are the only certified bag of their kind in the UK.”
The new compostable carrier bags, which are made from a combination of natural materials, are strong enough to hold heavy, bulky items.
Unlike conventional plastic bags they have also been approved for use as food waste bin-liners.
This means, along with their contents, they can be turned into compost and used to help grow fruit and vegetables.
Last year the supermarket used 64 per cent fewer bags compared with 2006, when industry-wide reduction targets were first set.