All Corningware products are microwave safe. Even the Corningware French White Gold cookware with the gold band around the edges is safe to use in the microwave. The Corningware line of bakeware is also suitable for use in the refrigerator, freezer, oven and dishwasher.
Corningware is a line of baking dishes made from a glass-ceramic material much like the type used in the 1950s on the nose cones of rockets to absorb dramatic temperature changes upon entering and exiting the Earth's atmosphere. Corningware does not absorb stains or odors, and it can go from freezer to oven without danger of breaking.