Abstract: It has been studied the utilization of cassava leaves as a source of livestock feed supplements by in-vitro for buffalo milked that maintain traditionally. The purpose of this research is to evaluation the utilization of Cassava Leaves Flour (CLF) as a food supplement concentrate in pellet form for buffaloes and its influence on rumen characteristics. Rumen liquid taken from the Slaughter House. The research is an experiment using the Completely Randomized Design (CRD) that consist of four treatments and five replications. The treatment were : 1. Feed A+ 0% CLF; 2. Feed B + 10% CLF; 3. Feed C + 20% CLF and 4. Feed D + 30% CLF. The variable was observed the concentration of NH3, bacteria count, total VFA production, Dry Matter Digestibility (DMD) and Organic Matter Digestibility (OMD) in the rumen. The result of this research indicated that the giving of Cassava Leaves Flour (CLF) as the source of carbon frame which can manipulating rumen with by pass protein is significantly (p<0.05) increase NH3, bacteria count, VFA production, dry matter digestibility and organic matter digestibility of rumen liquid. The Giving CLF up to 10% (treatment B) can be used as source of feed supplement for buffaloes that kept traditionally thus can improve the productivity of livestock.