TV viewers look unlikely to see a reality show about Amish youth facing the modern world following protests.
The programme, tentatively called Amish in the City, planned to show five young people from the reticent religious group living with mainstream youth.
But more than 50 US lawmakers have written to Viacom accusing the media giant of exploitation and bigotry.
CBS television - which Viacom owns - put a show with a similar concept on ice last year after criticism.
CBS chairman Leslie Moonves joked earlier this year that although a reality TV series called The Real Beverly Hillbillies had been shelved, the Amish "don't have quite as good a lobbying effort," the New York Times reported.
But a group has encouraged people to write to Viacom to protest against the Amish show.
Tim Marema of the Center for Rural Strategies told the New York Times the show would be "another way of attacking rural people... because of where they're from, what they look like, what they sound like."
"What CBS and Viacom are saying about the Amish is they're rural and therefore they don't count," he charged.
And two senators from Pennsylvania - which has America's best-known Amish community - wrote to complain.
"We know of no other reality series that singles out the beliefs and practices of a specific group of people as a subject for humour," the letter from Senators Arlen Spector and Rick Santorum said.
"For almost three centuries, the Amish have lived the way they do out of piety and conviction, not out of ignorance. If, by producing this show, you fail to respect that, you will be opening yourselves to charges of bigotry."
MediaPost reported that Mr Moonves had been ambiguous about the status of the show in a conference call with reporters this week.
He said it was in development but "has not been pushed forward".
Rumspringa
The Amish shun contact with the wider world, living in tight-knit communities with little modern technology.
But young adults can explore modern life in a custom called rumspringa, which could allow some to participate in the proposed show.
CBS halted work last year on a show based on popular 1960s sitcom The Beverly Hillbillies, about a poor mountaineer who becomes rich when he discovers oil on his property.
Members of the United Mine Workers of America, which represents 100,000 workers, said the show would be offensive to rural communities.
"This plan - to take a poor rural family, place them in a Hollywood mansion and ridicule them on national television - is repugnant to me and to the union members I represent, " union president Cecil E Roberts said last year.