The use of ceramics and glass as reactor materials is very promising for hightemperature and corrosive applications in microprocess engineering. Ceramic materials in particular demand more effort in the fabrication processes and joining techniques than metals or silicon. Notwithstanding these obstacles, several components have already been developed and successfully applied for chemical or thermal applications. Glass microreactors have been developed and manufactured over recent years by several companies. Several techniques, such as sand blasting, standard photolithography with wet etching have been used, as well as mechanical methods. A very interesting material is a photostructurable glass like FOTURAN, which allows the very accurate manufacture of fine channels and chambers with high aspect ratio. The manufactured structures are connected by diffusion bonding to form three-dimensional channel structures.