No, the frosting does not need to be refrigerated. For example, brownies frosted with this Brown Sugar Frosting would be fine left out on the counter for 2-3 days if the pan was tightly covered with aluminum foil. That said, we usually refrigerate our frosted desserts to keep the baked good from going stale even if the frosting would be fine. We think frosting tastes best at room temperature so we will then remove the item from the refrigerator a couple of hours before we will serve them.