Can I run 64-bit windows if device drivers aren’t of 64-bit?

Currently I’m using a 32-bit version windows OS. Now I want to upgrade it to a 64-bit version of windows OS, but my device drivers are of 32-bit. Is it necessary to use 64-bit driver’s of my devices to work all the hardware devices on 64-bit Windows? Can anyone from techyv tell me whether 64-bit drivers are necessary or not?
