Roger Bolton, who presents the Feedback programme on Radio 4, said the BBC was "coming up short".
He told Radio Times magazine that "just six months after the Archbishop of Canterbury called for broadcasters to take religion seriously, it seems the BBC is doing anything but".
Bolton said that promoting "knowledge and understanding" was a key role of a public service broadcaster.
Citing reports that a "BBC revamp will counter Christian 'bias'," he added: "Perhaps it's not Christian bias we should worry about but something far more worrying when it comes to understanding and interpreting our modern world - a bias against taking religion seriously."
Bolton told the magazine: "How can young people and immigrants to this country understand the UK without learning of the crucial role Christianity has played in the formation of its political structures and culture?
"How can people feel they're being welcomed as equal citizens if we don't bother to find out about what is often the most important part of their life, their faith?
"How can we understand what's going on in the Middle East, for example, without knowing about the Shia/Sunni split?
"This is not about promoting faith, it's about promoting knowledge and understanding - surely a central role of a public service broadcaster?
"But the BBC is coming up short."
Bolton also said that Songs of Praise, "one of the longest-running programmes of its kind anywhere in the world", might not be made by the BBC in future - although it would still air on the corporation.
He said: "For the 55 years of its existence this shining light of traditional religious broadcasting has been made by the BBC. But for how much longer?
"The BBC's own in-house team - along with independent producers - have been invited to tender for a three-year contract to continue to produce it, which they may not win.
"Why should viewers care? Isn't the important thing that the programme is being made, not who makes it? As a former independent producer I have a lot of sympathy with that view but, frankly, I'm more worried by the BBC's whole approach to religion."
His comments come as the corporation's head of religion and ethics, Aaqil Ahmed, leaves the BBC and James Purnell takes overall responsibility for religious programming, adding to his brief of head of radio and education.
Bolton complained that the BBC does not have a separate commissioning editor in TV for religious and ethical programmes.
"Whereas BBC News has editors for almost everything under the sun, from business and economics to the arts and sport, it doesn't have one for religion," he said.
A BBC spokeswoman said: "We take religion incredibly seriously, that's why for the first time it will be represented at executive level at the BBC, and why we are asking religious leaders to help us shape and do more across all of our diverse content - including for Christianity."
