Supercritical water (SCW) has been investigated for about 20 years for chemical reactions and processes. Water above its critical point (Tc = 374 °C, pc = 22.1 MPa, ρc = 0.322 g/cm3) has remarkable tunable properties and has been at the origin of a number of major developments especially due to its environmental innocuousness. SCW has been extensively used in the last 15 years to perform hydrolysis reactions. We propose to discuss in this book chapter the main fields of the application of the SCW hydrolysis reactions: (1) biomass liquefaction toward biofuels and platform molecules and (2) material recycling.SCW has been identified as an efficient medium in the transformation of biomass. Actually, Supercritical Biomass Valorization is a new generation of SCW-based technology, following the R&D development performed in SCW Oxidation. Two main routes can be investigated: the SuperCritical Biomass Gasification process and the SuperCritical Biomass Liquefaction process. Moreover, at present, the increase in the plant sourcing in the chemical industry is inescapable because of the social request for low environmental impact products and the high prices of products from fossil resources. In this context, biomass is particularly interesting because it is abundant and can be easily mobilized. Since lignocellulosic materials constitute approximately 95% of the total plant biomass, the discovery and the investigation of novel and effective pathways for their conversion are very important. In this chapter, we will present the direct SCW liquefaction of this new resource of carbon in order to produce two types of “biobased” products: 2G biofuels and platform molecules.In the context of a sustainable society, material recycling has an important role to play. Nowadays, the industry cannot produce consumer goods or industrial products without thinking about the future of each product in an environment and energetic point of view. Therefore in the field of environmentally friendly processes, a major challenge is the recycling of man-made materials. SCW has also been identified as an interesting medium for this aim. In this chapter, we will present two major aspects of material recycling using SCW: recycling of plastics and composite materials. We will see that hydrolysis reactions can be completed with alcoholysis reactions using near- and supercritical alcohols.< Leer menos