The aim of present investigation was to screen the microorganisms isolated from various samples such as soil, cattle dung and decaying woody material capable of degrading cellulose. A total 43 bacterial and 16 fungal isolates were retrieved from three different samples by serial dilution plating technique using carboxymethylcellulose (CMC) agar medium. All the bacterial and fungal isolates were screened for cellulase production on the basis of zone of hydrolysis on CMC agar medium. Out of 43 bacterial isolates, 13 bacterial isolates showed zone formation and three isolates i.e. SB2, SB4 and SB10 showed maximum zone of hydrolysis. Out of 16 fungal isolates, 10 fungi showed the zone formation on CMC agar medium and WF1 showed maximum zone. Cellulase activity of the isolates showing maximum zone i.e. SB4 and WF1 was determined and found to be 276.83 IU/mL and 230.62 IU/mL, respectively.