Roadside signs have been installed around the district urging people not to litter and make sure all their rubbish is taken home.
Lewes District Council is highlighting the cost of picking up litter and street cleansing across the district, which amounts to £800,000 annually.
Councillor Julie Carr, Cabinet Member for Recycling and Open Spaces, said: “It is a priority for us to keep our district clean and tidy.
“Most people value our well-kept environment but there is a minority of offenders who carelessly throw litter out of car windows or leave it behind in public places.
“These irresponsible individuals are not only damaging the area we live in but unnecessarily costing £800,000 a year in clear-up expenses that we would much rather allocate towards priority spending. This unacceptable behaviour must stop.”
Littering is a criminal offence and carries a maximum fine of £2,500.
Councillor Sharon Davy, ward councillor for Chailey Barcombe and Hamsey, said:
“Littering is a serious offence and these signs are a reminder to those who flout the law. The council will prosecute offenders whenever possible and investigate all reports of littering from vehicles.”