Huskyquilter -- I would definitely prewash the flannel. It sometimes shrinks a lot and sometimes not much and how much you paid does not seem to have anything to do with how much it shrinks. I made a lot of receiving blankets (close to 100) and I had pieces cut WOF square. I had as much as 6" shrinkage (I prewashed in hot water and dried hot figuring there could be some soiling needing the hot wash) and as little as no shrinkage in the same brand of flannel.