Yes, the Corningware glass cover is microwave safe. Corningware glass lids are a great way to keep food fresh while reheating. Corningware can withstand high temperatures, so it's no surprise that its lids can go in the microwave. Additionally, Corningware glass lids are shatter-resistant, making them a safer option than other types of microwavable lids. While Corningware glass lids are an excellent option for reheating food, do not use them for cooking food from scratch.