No problem, I do it all the time. It also helps to keep the weeds down in between the rows.

Works like a charm. My pumpkin plants really seem to enjoy climbing my corn. The only complaint that I have is that one pumpkin formed with the plant wrapped around a taller corn stalk. It bent the top of the stalk as it got bigger. It didn't have any corn up there anyway, and I had already harvested from that stalk, but it's something to keep in mind.

Jill

what about watermelons and cantelopes also in between the corn?

Growing pumpkins between corn is a great idea. As stated already it keeps the weeds down between the rows. I grow it between the rows and along the perimeter to keep the racoons away from the mature corn. They tend not to cross the prickly vines.