The MPS Envirlope features a paper-based transparent window instead of plastic film.
The new window material is made from a cellulose base wood pulp sourced from managed forests that meet the Sustainable Forestry Initiative Standard. It is fully recyclable and biodegradable.
Rob Fagnani, managing director of MPS, said: "The Envirlope is no different to any other window envelope and costs about the same.
"Normal production processes can be applied and it carries the same qualities as a conventional envelope, except its 100% biodegradable.
"What's more, if the envelopes are made from a range of 100% recycled and FSC-approved paper stocks, the mailing pack can be made even more environmentally friendly."
The Envirlope has also been approved by postal authorities in America and France.