One in six people also admitted waiting at least a month before washing their bed sheets.
Experts say up to ten per cent of the weight of an unwashed pillow can be made up of dead skin and mites, with a dirty bed having about ten million bedbugs.
It would come as no surprise to most mothers but under 25s were found to have the dirtiest bed sheets with one in 10 admitting to washing theirs only six times a year.
In contrast, house-proud over 55s air their dirty laundry on average three times a month.
Londoners were the worst culprits when it comes to unwashed bedding, the survey of 1,029 men and women from across the UK, found.
The capital was closely followed by Brits in the North East, and the South West, also keeping dirty sheets on their bed for more than a month.
Regions with the dirtiest bed sheets:
1. London (24 per cent)
2. North East (22 per cent)
3. South West (21 per cent)
4. East Midlands (19 per cent)
= 4. South East (19 per cent)
6. North West (18 per cent)
= 6. West Midlands (18 per cent)
8. Wales (17 per cent)
9. Eastern England (16 per cent)
10. Scotland (15 per cent)
11. Yorkshire (13 per cent)
12. Northern Ireland (8 per cent)
Note: per cent based on those washing their bedding just once a month or less frequently.