With summer approaching, Bolton On Dearne residents are arming themselves with fly swatters and insect spray.
They have told us there has been an increase in the pests - which are believed to be coming from the nearby waste recycling centre at Manvers.
The Environment Agency's been investigating the issue this week - as it got temporarily worse during maintainence work.
But, the owner of the nearby Corner Cafe says it's a year round problem, which needs tackling before it gets warmer.
Renewi - which runs the site - says it is already aware of concerns and has taken immediate steps to minimise flies.