BACKGROUND: The correct usage of  wastes in animal nutrition causes  decrease in environmental pollution. Apple pomace as an energetic matter and source of digestible fibers for ruminants is a proper alternative for forage. OBJECTIVES: The aim of this experiment was to investigate the effect of diets containing dried apple pomace on digestibility, rumination, microbial fermentation and blood glucose and urea of Arabi sheep. METHODS: In the first step, 0, 10, 20 and 30% dried apple pomace replaced with alfalfa were used in the experimental diets. According to the result, gas production and digestibility of diet containing 30% dried apple pomace was higher than the other diets (p<0.05). Therefore, in the second step, 8 Arabi sheep were fed with diet without apple pomace (control) and diet containing 30% apple pomace for 45 days. RESULTS: The result showed that nutrient digestibility (dry matter, organic matter, NDF and ADF) were not significantly affected by the diets (p>0.05), but rumination activity of diet containing apple pomace decreased (p<0.05). Blood metabolites (glucose and urea) showed no significant differences between experimental diets, but blood glucose was higher in control treatment. Rumen ammonia nitrogen concentration was 14.48 and 17.49 mg/dl (p>0.05), and pH was 6.30 and 6.16 for control and apple pomace treatment, respectively (p<0.05). The rumen protozoa numbers increased with apple pomace (p<0.05). Diet containing apple pomace increased gas production potential and digestibility of wheat straw by rumen microorganism and bacteria (p<0.05). CONCLUSIONS: The results of this study suggest that alfalfa replaced with 30% dried apple pomace in Arabi sheep’s diet can improve digestive activity of rumen microbes and nutrient fermentation and digestibility.