what a lot of discussion this topic always generates!! I never prewash as I like the fabric as it comes off the bolt. I always wash my quilts when they are finished, and have never had a problem - some of the fabrics don't even wrinkle up all that much - depends on how much quilting. It really is a personal choice, and I can't see the point of washing all the sizing out and then starching the hell out of the fabric to make it stiff again!