A lot of times. Notably in the first round of comics, way back in the beginning of the X-Men, and he died more recently in the Messiah CompleX arc when he was shot in the head by Bishop. However, he's managed to come back every time he died, whether by the Shi'ar stepping in to help him, duplicate images of him being killed, or 'the bullet hit him in the head, yes, but it didn't kill him' logic.
So yes, Xavier dies, a lot, but he always comes back. I hope this is what you were looking for.