Call it a lack of Christmas cheer.

An organization that promotes the separation of church and state plans to deploy more than 50 billboards in the Sacramento, Calif. area to highlight atheists who are ignoring religion and the December holidays' spirituality, its co-president said Monday night.

The messages are part of the Madison, Wis.-based Freedom from Religion Foundation’s campaign to encourage non-believers to “come out of the closet” and be open about their atheism, Annie Laurie Gaylor told FoxNews.com.

But not everyone is ready to turn their back on religion during the holiday season.

“While I’m not happy about these billboards, I am certain people still, when they look deep down in their soul and in their heart, find a spark,” Bishop Jaime Soto, of Sacramento’s Cathedral of the Blessed Sacrament, told KTXL-TV. “They believe in a higher power.”

Gaylor stressed that the campaign isn’t to insult Christmas or any other holiday, but to encourage people to simply ignore the religious undertones.

“The whole month of December is taken over in a celebration of the religious beliefs, in particular Christianity, and it’s just as if the whole month turns non-believers into outsiders,” she said.

The group sought out Sacramento-area members to share their points of view about being non-believers, and the response was so positive that the organization had to contract with a second billboard company to meet the demand, Gaylor said.

“I believe in people, not gods,” reads a testimonial from Liz Shoemaker, a Sacramento teacher, KTXL reported.

“Integrity and compassion require no gods,” say Matt and Kimberly Martin, a Sacramento couple.

The campaign, the costs of which Gaylor declined to disclose, is set to run through the holidays.

“We’re a free society, and it’s the free marketplace of ideas,” Gaylor said. “It should be debated publicly. What’s wrong with open debate?”