In the purpose of modelling the chemistry of the combustion of an organic compound or, what is the actual case in most practical applications, of a mixture of organic compounds, in the large temperature field which can be observed in an engine or in a burner, it is necessary to consider several thousands of elementary reactions. Since the only systematic way to write such huge mechanisms is an automatic procedure, several attempts were performed to develop computer tools for the construction of mechanisms. This paper describes a computer package which permits the automatic generation of detailed oxidation and combustion kinetic models in the case of normal alkanes, isoalkanes and ethers. The detailed mechanisms obtained have been successfully validated in the case of methane, n-butane, n-heptane, n-octane, iso-octane, n-decane, mixtures n-heptane-iso-octane, mixtures n-heptane-methyl tert-butyl ether and mixtures n-heptane-ethyl tert-butyl ether in a wide range of temperature (from 600 to 2100 K) and pressure (from 0.04 to 10 atm). By using chemical lumping techniques, these mechanisms can be drastically reduced. However, further reduction is needed for computer fluid dynamics (CFD) codes.