Up to now, many studies have been trying to reveal the impact of oil palm plantations on tropical peat on the global carbon (C) balance. Although there are some publications on soil respiration in oil palm plantations on peat soil, information on carbon dioxide (CO₂) emissions from palm litter (pruned fronds) decomposition is limited. Therefore, we quantified the CO₂ emissions through frond decomposition in two different mature oil palm plantations established on peat, an industrial plantation in Riau and a smallholder plantation in Jambi, Indonesia. Frond decomposition was measured using a litter bag method and the decomposition rate constant was determined using a negative exponential equation. Annual CO₂ emissions from frond decomposition were estimated at 1.48 and 1.12 Mg C ha⁻¹ yr⁻¹, respectively, in industrial and smallholder plantations. As a result, CO₂ emissions from frond decomposition accounted for 10%-14% of heterotrophic respiration from mature oil palm plantations on tropical peat.