Microbial transformation of organic matter is thought to stabilise carbon in soil. When soil microbes have a high carbon use efficiency (CUE), a high proportion of the metabolised carbon is incorporated into the microbial biomass, thereby promoting this in-vivo stabilisation of carbon. Managing CUE could therefore become a strategy to support C sequestration. Soil pH was shown to be a major driver of microbial CUE in agricultural soils and therefore, management practices to control soil pH, such as liming, could serve as a tool to modify microbial physiology. However, the potential to actively manage CUE via liming is unclear. To address this question, the long-term effect of liming on CUE was investigated on soils from three European long-term field experiments (Versailles Bare Fallow ‘42 Parcelles’, Store Jyndevad ‘P and liming experiment’and Dürnast ‘Kalkversuch 016’). In addition, control soils were limed in the laboratory to investigate direct liming effects on CUE by accounting for lime-derived CO2 losses (δ13C signature). Preliminary results suggest that the long-term effect of liming on CUE is dependent on the pH range in which changes occur. Direct liming led to an increase in soil pH, but did not increase CUE in short-term. We will present effects of long-term liming and direct liming on soil microbial CUE and highlight the potential of manipulating CUE via liming.