Declining fossil oil reserves, skyrocketing prices, unsecured supplies, and environmental pollution are among the many energy problems we are facing today. It is our conviction that renewable energy is a solution to these problems. The objective of this research is to study and develop thermochemical processes for converting bulky and low-energy-density biomass materials into biofuels and value-added bio-products. In our study, a Parr high-pressure-reactor was used for the hydrothermal process. Supercritical water condition was created at high pressure (374C, 22.1MPa). Corn residue was used as a model feedstock. Process variables to be studied include temperature, time, catalysts, solid loading, gas composition, and liquid composition. The products from the supercritical water assisted reactions consist of three phases: water soluble phase, heavy oil phase and gaseous phase. The yields and chemical properties of individual phases were also determined. On the other hand, a novel pyrolytic process for the recovery of fuel gas and liquid from agricultural wastes was developed. This new process is an environmental-friendly technique in which energy transfer to the waste occurs by microwave radiation; it has shown several advantages over conventional pyrolytic processes and represents a new opportunity to use pyrolysis to treat solid wastes as it overcomes the major difficulties that arise from other alternative methods.