The subject of this thesis are both available and potentional gaseous and liquid biofuels. The thesis deals with their detailed description and comparison. The first part describes the current legislation and the basic types of biofuels. The main part focuses then on biofuels themselves, their characteristics, production, utilization, and their impact on environment. In further parts, emissions created during the cycle of production and distribution of biofuel are characterized. Last part brings comparison of biofuels from different points of view, and recommendation of the alternative ways of production of gaseous and liquid biofuels from renewable resources of energy.