Experiment was conducted to evaluate in vitro greenhouse production effected by coconut oil (CO) levels. The 2x4 factorial design was used in this experiment. The first factor was concentrate (without or with 20% - C0 or C20) added to Para grass as the substrates (DM basis) and the second factor was the addition of CO levels of 0, 2, 4 and 6% (CO0, CO2, CO4 and CO6, respectively) with 3 replicates. Rumen fluid of goats fed only Para grass was used as inocculum. Gas production was measured at 0; 3; 6; 9; 12; 24; 48; 72 hours. The concentrations of CH4 and CO2 were analyzed at 24, 48 and 72 hours by Biogas5000 Geotechnical Instruments (UK), England. Results of the experiment showed that the accumulated in vitro CH4 production at 72 hours for the C20 treatment (41.5 ml/g OM) was significantly higher (Ptreatment (37.0 ml/g OM). There was a significant, gradual reduction of CH4 production (Pvitro CO2 production at 72 hours. The in vitro OM digestibility was significantly higher (P6.0% (PPara grass with and without concentrate gradually reduced greenhouse gases production, however the OM digestibility was also decreased. The in vivo studies should be performed to determine optimal levels of coconut oil, as a dietary supplement, in goat diets.