The present investigation had been focused on evaluating the effect of feeding a rumen modifier which is mixture of RM-7 [neem seed cake (Azadirachta indica), mahua seed cake (Madhuca longifolia), fennel seed (Foeniculum vulgare), harad (Terminalia chebula), fruit pulp of bahera (Terminalia bellirica), fruit pulp of amla (Phyllanthus emblica) and ajwain seed (Trachyspermum ammi) in 2:2:2:1:1:1:1 proportion] and sodium sulphate on enteric methane production and improved animal performance. Twenty one growing buffalo calves divided into three groups of seven animals each were selected for the experiment. All the animals were fed iso nitrogenous diet with basal diet i.e. concentrate and roughage in 50:50 ratio. The control group (T1) was fed basal diet, the treatment group (T2) was fed basal diet plus rumen modifier (RM-7 at 2% DMI + sodium sulphate at 0.06%) and the treatment group (T3) was fed basal diet plus rumen modifier (RM-7 at 4% DMI + sodium sulphate at 0.06%) for a period of 120 days. Daily dry matter intake and body weight gain of the animal showed no significant (P>0.05) difference among treatment groups. The percent reduction in methane production was significantly (P<0.05) less in treatment groups when compared to control.