I ALWAYS wash my fabric first and put it in the dryer. I have not ever had a problem with flannel shrinking. This baby quilt has been washed and dryed several times now and it is holding up well with no shrinking. Now, I have never used flannel on a large quilt, but I would assume, if a quality flannel is purchased, you should have no problem with larger pieces. The flannel that I used in this baby quilt is from Moda. I like their flannel for baby quilts as it's so soft and not stiff. I definitely would NOT buy flannel at Walmart. I hope this helps. Happy quilting!