my first quilt that I used flannel backing, I did not wash the flannel. Then I read on this board you should wash the flannel because it shrinks so much. Oh durn, and I had hand quilted this quilt also!! So when I washed it, I washed it in cold water, and put it in the dryer for about 30 minutes and then hung it over the line to dry. I think the quilt still looks good in spite of the fact I did not prewash the flannel! And this was WalMart flannel too.