Anaerobes grow in the absence of oxygen were predominant in the rumen region of the cattles such as goat, sheep and cow. The role of anaerobic microbial flora in cattles is very broad and the intensive research in this area was carried out here with the special reference to evaluation of plant fibre degradation by anaerobic microflora. The plant fibre degradation in cattle was evaluated by anaerobic microbial flora. The results reveal that the anaerobic fungi play a major role in plant fibre degradation than the bacteria and protozoa. The ruminants feed on cellulosic agricultural by products like cereals straws,stovers, sugarcane bagasse and tree foliages. The ruminants have the efficiency to utilize a wide variety of feeds due to the presence of bacteria, ciliate protozoa and anaerobic fungi. Hence the rumen of cattle has a rich potential of microbial diversity. The present study has been undertaken by collecting the rumen fluid from cattles such as sheep and goat to analyse the protozoa in the rumen fluid microscopically and by evaluating the fibre degradation activity by anaerobic flora.