We have demonstrated for the first time the creation of graphene oxide and graphene-based carbon aerogels by freeze-drying of graphite oxide/water dispersion. The graphene oxide aerogel consists of sheet-like nanocarbon structures, and could be significantly reinforced by small amounts of water soluble polymers. Controlled thermal treatments reduce graphene oxide to graphene and restore the electrical conductivity of the graphene aerogel. The graphene aerogels are electrically conducting, with extremely high surface-area-to-volume ratio, could outperform conventional carbon aerogels for applications such as sensors, actuators, high performance polymer nanocomposites, and electrochemical applications such as porous electrodes for batteries, fuel cells, and supercapacitors.