In this research, the combustion behavior of six Turkish crude oils (light and medium type) was investigated by thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) methods under atmospheric air in the absence of rock matrix. Two main reaction intervals were observed on all thermograms known as low temperature oxidation (LTO) and high temperature oxidation (HTO) regions. The resulting curves showed that the mass loss under combustion is accompanied by exothermic peaks due to the oxidative degradation of crude oil components. Heavier oils with greater asphaltene content were exposed to more heat release during oxidation reactions. By the increment of heating rate, not a remarkable variation was observed in apparent activation energies whereas the heat emission of crude oils decreased. Based on the model free and model fitting kinetic approaches, heavier oils had higher apparent activation energy and Arrhenius constant values for all oxidation regions. (C) 2014 Elsevier Ltd. All rights reserved.