Liming and nitrogen fertiliser application are common management practice used to achieve optimum production in reclaimed peats for agriculture. The effects of lime and nitrogen addition on carbon mineralisation have been widely studied, but the results are highly varied. These inconsistencies are thought to have been attributed to differences in the quality of substrates in the soils used in those studies. To test whether the effect of lime and nitrogen addition on carbon mineralisation of peats depends on peat substrate quality, two tropical peats varying in carbon chemical structure as determined by the solid-state 13C nuclear magnetic resonance (NMR) were incubated in the laboratory experiment for 35 days. Carbon mineralisation in peat of high C/N ratio increased with nitrogen addition, but decreased in peat of low C/N ratio. Liming stimulated carbon mineralisation in both peats but the response was greater in peat of high C/N ratio than that of low C/N ratio. Results of this study demonstrate that liming and nitrogen fertiliser application influence carbon mineralisation of peats with the degree of carbon mineralisation varied with the substrate quality of peats