The survey led by www.youngpoll.com has revealed that 11 per cent of the youngsters believe that it was the birthday of Father Christmas.
Another six per cent thought December 25 was set aside just so they could get some presents.
Almost a quarter of youngsters did not know the reason for celebrating Easter.
Three per cent thought it to be the invention of chocolate, and nine per cent believed it was the Easter Bunny's birthday.
However, 77 per cent knew it was to celebrate the resurrection of Christ.
"It's shocking to think that so many children aren't aware about the reasons behind Christmas and Easter," the Daily Express quoted spokesman for www.youngpoll.com, as saying.
"But for children nowadays, Christmas is about receiving presents, having a nice family dinner and decorating the house, while Easter is about how many chocolate eggs they get," he added.
The poll of 2,000 children, aged eight to 15 showed that almost 42 per cent had no idea that Christ died on Good Friday.