Abstract: Background and Objective: Leaf waste from palm oil plants has not been widely utilized by farmers due to the low biological quality of the palm leaf midrib. Efforts to optimize the utilization of waste-derived feed include physical, chemical or biological processing or a combination of those techniques. This research was conducted to determine the best palm leaf processing method to increase the nutrient content and digestion of the palm leaf midrib. Materials and Methods: This study used completely randomized design with 5 treatments and 4 replications. Treatments were = A: Control (without treatment), B: Physical processing (steam), C: Chemical treatment (ammonia), D: Biological treatment (ensilage) and E: Chemical-physical combination (steam-ammonia). The parameters that were measured included the nutrient content, dry matter digestibility, organic matter, crude protein, in vitro fibre fraction and rumen fluid characteristics. Results: The processing of oil palm leaf pole with ammonia (treatment C) resulted in better nutrient contents and in vitro digestion for cut palm leaves than other treatment methods (p<0.05). Leaves in treatment C had the following nutrient contents: Dry matter (40.51%), organic matter (84.25%), crude protein (13.75%), neutral detergent fibre (NDF) (54.76%), acid detergent fibre (ADF) (42.54%), cellulose (20.77%), hemicellulose (12.22%) and lignin (10.74%). In vitro digestion resulted in the following nutrient contents: Dry matter (34.53%), organic matter (41.65%), crude protein (45.32%), NDF (30.71%), ADF (24.28%), cellulose (31.39%) and hemicellulose (51.78%). The rumen fluid characteristics were as follows: pH (7.02), VFAs (135.93 mM) and NH3-N (58.90 mg/100 mL). Conclusion: Treating cut palm leaf poles with ammonia results in better nutrient contents and in vitro digestion than physical processing (steam), biological treatment (ensilage) or a combination of physical and chemical processing (steam-ammonization).