Buses are set to carry a slogan saying: "There's probably no God" for an atheist advertising campaign.
The British Humanist Association, which objects to Christian ads, has raised £18,000 to pay for the ads in London.
It will read: "There's probably no God. Now stop worrying and enjoy your life."
Atheist Prof Richard Dawkins, who pledged £5,500, said: "Religion is accustomed to getting a free ride. This will make people think."
But the Methodist Church thanked Prof Dawkins for "getting God onto London buses".
Rev Jenny Ellis said: "We are grateful to Richard for his continued interest in God and for encouraging people to think about these issues."
-Ananova