The term biomass covers a wide range of products, by-products, and waste streams derived from forestry and agriculture, as well as from municipal and industrial waste streams. Biofuels are the only renewable energy sources that have the potential to directly replace fossil fuels. Over the past decade, bioenergy technologies achieved significant cost reductions in several important areas including: dedicated large- and small-scale combustion; co-firing with coal; combustion of municipal solid waste; biogas generation via anaerobic digestion; and in district and individual household heating. In certain geographical areas, cost reductions were also realized in liquid biofuels such as bioethanol and biodiesel. Biomass fuels and residues can be converted to energy via thermal, biological, mechanical, or physical processes. One of the most significant barriers to accelerated penetration of all biomass conversion technologies is that of adequate resource supply. Feedstock costs vary widely depending on the type of biomass and the transport distance. The most economical approach is to use bioenergy on-site, i.e., where biomass residue is generated. Bioenergy is the largest contributor to renewable energy supply. In 2005, total bioenergy supply was 160 million tons of oil equivalent (Mtoe) throughout the world. The present study reviews the production, consumption, and technologies for biofuels in some developed and developing countries.