The processing of oranges for juice extraction generates bagasse as an agro-industrial residue; this residue represents about 50% of the total volume of the fruit, consisting of peel, seed, and pulp. Promoting the use of residues like the orange pomace may provide economic and environmental benefits, and, for this propose, the complete characterization of the material becomes essential. In this work, the bagasse from Matao-SP was characterized in terms of chemical properties to expand its use. Chemical analyzes were performed using specific TAPPI and NREL standards for lignocellulosic materials and showed that orange waste contains, in dry mass, 2.9±0.2% of ash, 12.3±0.9% of moisture, 19.3±0.9% solvent extractives, 38.5±1.5% cellulose, 33.1±2.0% holocellulose, 24.0±2.0% hemicellulose and 2.9±0.5% lignin. The useful chemical and nutritional composition of orange pomace allow its application, for example, in new materials and nanotechnology.