The hydrothermal carbonization (HTC) is feasible to produce valuable products from multiple organic residual and waste materials. These products may be humus or a certain kind of biochar, which is used as a fuel most suitable for storage and transport or maybe as a top soil conditioner. Furthermore, the process enables the production of specialized, nanostructured materials from biogenic resources. In contrast to other processes of biomass conversion the demands on the raw materials are quite low. HTC offers the opportunity for the utilization of especially wet biomass with low contents of valuable components like edible oil, starch or sugars. The article reviews the state-of-the-art of science regarding HTC and complements it with own research.