3D printing with carbon concrete: technology and the first test results. 3D printing with cement-based materials requires appropriate solutions for the integration of reinforcement during the manufacturing process. The article at hand presents a new technology developed for this purpose which is based on using mineral-impregnated carbon-fibre (MCF) composites. This new type of non-corrosive reinforcement yields excellent mechanical performance, high sustainability and durability. Crucial is however, that it offers extremely high technological flexibility, since MCF can be easily shaped in the fresh state and processed fully automated. The article describes a new nozzle developed for the integration of MCF reinforcement directly into concrete filaments in the context of the 3D printing based on layered extrusion. Three carbon yarns were introduced simultaneously in each concrete layer. The existing testing procedures were adapted for assessing tensile and flexural behaviours of printed carbon concrete as well as of bond between reinforcement and concrete. The experiments showed mechanical performance comparable with that of textile reinforced concrete made with carbon fibre. The research work proved the feasibility and very high potential of the new technology with respect to digitation and automation of concrete construction.