Soil organic matter is the largest carbon pool in terrestrial ecosystems. Consequently, even small changes of soil organic carbon dynamics may have significant impacts on feedbacks to global climate. The fate of soil organic matter in ecosystems is determined during its decomposition by microbial metabolic activity. A driving force of microbial activity in soil is the need of microorganism to acquire energy from organic matter. Thermodynamic limitations and energetic properties of organic matter can hamper microbial activity. Despite the central role of energy in soil organic matter decomposition, energetic approaches have long been peripheral in soil organic matter research. Early uses of calorimetry to investigate microbial activity in soil date back to the 1980s, but only within the last 15 years have calorimetric approaches come slowly back on the research agenda. Currently calorimetric approaches gain momentum in soil organic matter research. This presentation aims to give an (incomplete) overview on how calorimetry is used to investigate organic matter decomposition in soil. The use of calorimetry reaches from isothermal microcalorimetry – to investigate microbial activity and energy use efficiencies – over differential scanning and bomb calorimetry – to analyse energetic properties of organic matter – to calorespirometry, providing insights into microbial physiology during decomposition.