Silicon nitride monolithic structural ceramic components have recently been introduced as production parts in commercial aircraft turbomachinery pump and seal applications to take advantage of their unique thermomechanical properties. Additionally, extensive efforts are in progress to develop, evaluate, and productionize silicon nitride components for commercial aircraft turbomachinery hot sections, industrial power generation turbines, and automotive hybrid vehicle turbogenerators. AlliedSignal Ceramic Components has developed a family of in-situ reinforced silicon nitride materials for these applications and is developing and implementing a suite of component fabrication processes to achieve production-viable manufacturing of complex shaped components, including turbine seals, blades, nozzles, wheels, and combustors. A key focus of the manufacturing process development is the need to achieve low cost fabrication of components in order to meet cost targets required for commercial introduction. Finally, the status and plans for a number of aerospace, industrial, and automotive turbomachinery applications are discussed, including commercial aircraft turbomachinery production components (pump and seal parts) and development components (auxiliary power unit turbine blades and nozzles, and propulsion engine wheels and starter wheels), nozzle, blade, wheel and combustor components for automotive hybrid vehicle turbogenerators, and turbine blades and nozzles for industrial power generation gas turbines.