Characterization of organic matter attending biodegradability is a common practice when a bio-kinetic model is used to describe the reaction rates at which organic matter of wastewater is biodegraded. However, procedures for characterizing organic matter contained in feces have not been reported yet. This paper deals with the characterization of feces; two approaches for characterizing organic matter of feces are discussed based on physicochemical determinations and biological response during aerobic degradation. Application of those procedures leaded to characterization of feces in terms of chemical oxygen demand (COD) and mass units.