Biofuels represent an important category of green and alternative energy, and they have high potential to meet the energy demands of society. They are obtained from various renewable sources, which include energy crops, wood and wood wastes, agricultural by-products, and algae. Pyrolysis is an advanced technology to produce biofuels from biomass. In this review, we focus on analytical pyrolysis of biomass, in which a sample is decomposed with the help of heat treatment in an inert atmosphere. In a Py-GC-MS system, the pyrolyzer unit is connected to a gas chromatograph with a mass detector. We provide insight into the analytical pyrolysis of various biomasses and biomass components, decomposition pathways, formation of possible decomposition products and the effects of catalysts in the degradation of biomasses. Also, we discuss sample preparation and instrumentation for analytical pyrolysis. (C) 2014 Elsevier B.V. All rights reserved.