An acquaintance discovered the bodies of the two men in their late 50s or early 60s at the Batiscan-Neilson campground near Quebec City on Saturday.
A spokesman for the Quebec provincial police says the deaths did not seem criminal in nature.
No trace of violence was found on the bodies or at the site.
The deaths appear to be be due to carbon monoxide poisoning stemming from the camper's propane heating system.
A police investigation into the cause of death is underway.