The Sycamore BMW dealership showcased the new 5 Series and Mini models on Thursday night. The cars were parked outside and in the nave of the church, an area historically used as a marketplace.
The event was opened with a prayer that people were invited to participate in and a choir performed a short concert. Staff were on hand to give people tours and explanations of the building.
It's reported Peterborough Cathedral was paid to host Sycamore BMW but it's unknown how much they received.
Claire Lupin said on Facebook: "I know the cathedral will benefit greatly from the money they receive for this but its rather gross. Have you considered sponsorship? Coca cola maybe? or a Subway in the cloisters?"
Barbara Monzon added: "Disgraceful use of a cathedral... and you wonder why C of E is perishing?"
But Jonathan Hanley said: "Cathedrals should be looking forwards and be engaging in different ways with modern communities, rather than being stuffy old museums. This is not only good for the cathedral bank balance, but brings loads of people into the building that might never visit."
Peterborough Cathedral commented: "This is about welcoming people. Large numbers of guests will be here this evening and some of these will be people who would never otherwise set foot in the building.
"They can enjoy this beautiful, sacred space, maybe go on a tower tour and hear the Cathedral Choir sing, as well as look at the cars. We hope they have a very enjoyable evening and leave wanting to come back again soon."