Objective. The aim of the study is to determine the effect of different plant essence oil supplementation to TMR, concentrate and hay on methanogenesis and at 2, 8 and 24 hours (h) using in vitro gas production technique in cattle. Material and methods. Three fistulated Holstein dairy cows were used for rumen fluid collection for application of in vitro gas production technique. Four essence oils (T. vulgaris, O. vulgare, S. aromaticum, Z. officinale) were used as plant extracts. Results. Essence oil supplementation, particularly at increased doses, significantly decreased methane production for TMR, concentrate and hay at 8 and 24 h compared to negative and positive control groups (p<0.05). Among all plant extracts, Syzygium 200 ppm supplementation resulted the lowest methane production values(p<0.05). While methane production at 24 h in positive control groups were recorded respectively as 10.45, 10.75 and 10.07 for TMR, concentrate and hay, the values in Syzygium 200 ppm group were recorded respectively as 1.65, 3.28 and 1.98 for these feed groups. Conclusions. The findings of the study indicate that increased doses of essence oil supplementation significantly decrease methane production in ruminants. Hence, it is suggested that essence oil will be highly beneficial in ruminant nutrition.