Abstract: The aim of this study was to investigate effects of different levels of Clove Methanol Extract (CME) on methane production in ruminant with practical diets. Two experimental diets (diet1: 100% forage and diet 2: 100% barley) were used to investigate effects of 3 levels of CME (0, 0.5 and 1 ml) on methane production at 2, 4, 12, 16, 24, 48, 72 and 96 h of incubation. Gas production was continuously measured by EX-TEC HS 680 GC. Cumulative gas production was recorded at 2, 4, 12, 16, 24, 48, 72 and 96 h of incubation periods. Data processed in excel and analyzed using SAS statistical analyze software. Result show that Clove methanol extract in initial time of incubation (2 and 4 h) not affects on the decreased of methane production, but increase incubation time CME significantly decreased methane gas volume in two diets and all of CME levels and could significantly decrease methane volume in the treatment. According to result we could suggest CME for improve methane production in the in vitro condition and need further research for application CME in field of ruminant nutrition.