Tar generation in biomass gasification still poses a considerable challenge regarding its access to commercial stage. Along with experimental research, it is essential to develop comprehensive models of the process that allow accurate prediction of the resulting syngas composition, as well as tar generation. Traditionally, models have focused on defining heterogeneous reactions of char conversion, devoting limited attention to gas interactions. The present research offers a new wood gasification model for fluidized beds, characterized by a detailed definition of homogeneous reactions, considering both generation and evolution of created tar through oxidation, reforming and thermal cracking. The model succeeds in predicting gas generation, composition and heating value with a relative error similar or lower than analogue existing gasification models, as well as the order of magnitude of tar generation. (C) 2016 Elsevier Ltd. All rights reserved.