Differential scanning calorimetry (DSC) and simultaneous thermogravimetry/differential thermal analysis (TG/DTA) were used for the determination of reaction heats and mass losses, respectively, of oil shales for the temperature range of the drying/preheating process and retorting. The samples originated from the Stuart, Condor, Nagoorin, Lowmead and Duaringa Tertiary oil shale deposits in southeastern Queensland, Australia. The results showed that the enthalpy associated with retorting ranged between 68 J g(-1) and 194 J g(-1). The mass losses associated with drying/preheating and retorting were found to range between 1.0% and 6.0%, and 5.4% and 30.9%, respectively. A correlation between retort enthalpy and siderite and clay contents of the oil shales was established. The Duaringa shale sample was found to behave differently from the other shales.