The isolation, selection, adaptation and handling of native microorganisms, coming from organic waste, is an alternative to avoid the accumulation and the lack of the proper use of these undesirable materials. This organic waste is a source for obtaining microbial strains which are potentially producers of industrial enzymes and, at the same time, it works as substrate so that these organisms can transform it into compost or organic manure. In this work, 39 native strains of microorganisms with potential cellulolytic activity, coming from the organic waste of the urban and rural sector, from the Compostage Plant of Marinilla (Antioquia) municipality, were isolated, evaluated and purified. The waste was previously selected and then submitted to an aerobic degradation or compostage. The microbial strains were isolated in a selective medium with carboxymethyl cellulose (CMC), of the phases mesophile, tenmophile, cooling and maturation of the compost process. Eighty-two percent (82%) of the obtained colonies were identified, in principle, as Bacillus, because of their morphology and their reaction to the Gram coloration. The fungi population was seen only during the cooling phase. Then, the potential cellulolytic activity was evaluated qualitatively in a solid medium with the Congo Red coloration, with which the ii-endoglucanase activity was evaluated through the formation of clarified zones. Such staining was applied in two mediums with CMC with and without glucose. It was observed that 33.3% of the isolated organisms produced the enzyme in both mediums; however, 25.6% of microorganisms did not show the production of this enzyme, and only 15.8% did not require the inducer to produce it.