This study provides a preliminary assessment of the geothermal energy potential of the Mangyshlak sedimentary basin in western Kazakhstan. The assessment is done by utilizing the available data from the oil and gas industry such as reservoir temperatures and/or drilled wells' bottomhole temperatures. Depth-temperature profiles revealed that geothermal energy production is promising for Triassic units. The amount of geothermal energy in-place was calculated to be equal to 70 000 EJ, by calculating the amount of heat that will be released through cooling of the rock at a given temperature difference. A prospect potential of energy extraction of up to 1 500 EJ is expected if energy is extracted from the rock up to 7km depth, assuming 2% recoverability of these resources. The results also showed that the high quality reservoir intervals within Triassic strata make it possible to be utilized for direct electricity generation due to sufficient temperatures (>150°C) at the depth of 3-4 kms.