This experiment was carried out to investigate the effects of adding Poly-Ethylene-Glycol (PEG) on grape and lime pomaces on methane production by ruminal fermentation, digestion and metabolism energy. Grape and lime pomaces remained from in fruit juices were collected and were transferred to laboratory. The pomaces were dried (by fit ventilation ) and were milled (by sieve 1mm). Chemical compositions including CP, NDF, Ash, EE, GE, OM, NFC, TP and TT were measured . The gas production test for various ruminal fermentation periods and methane production were analysed using six treatments containing different amounts of grape pomace, lime pomace and control. Results were analyzed by R statistical software, using factorial design with three repetitions. Chemical composition of grape and lime pomaces were significantly (P<0.05) different. Methane production (in 24 hours for per 200 mg) of the grape pomace (with and without PEG) was 13.3 and 27.7 ml and for lime pomace (with and without PEG) was 73.8 and 67.3 ml respectively. In conclusion, a significant increase on digestion and metabolic energy was observed after adding PEG to grape and lime pomaces. Adding PEG to grape pomace increased methane production while it decreased methane production in lime pomace.