Objective. Determine the effect of some plant extract supplementation to Total Mixed Ration (TMR), concentrate and hay on volatile fatty acid (VFA) production at 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 supplementations to the examined feed groups had significant effect only on C2/C3 VFA level at 8 h in all feed groups (p<0.05). C2/C3 VFA level at 8 h significantly increased in the groups with Oregano 25 ppm supplementation for TMR and concentrate and in the groups with Thymol 25 ppm supplementation for hay. C3 VFA level at 8 h significantly increased in the group that received Syzygium 200 ppm supplementation for hay. Different plant extracts supplemented to TMR, concentrate and hay significantly affected C2, C3, IC4, IC5, C5 and C2/C3 VFA levels at 24 h (p<0.05). Conclusions. The findings of the study indicate that moderate doses of plant extracts result in increased VFA levels in ruminants while higher doses demonstrate the opposite effect.