Most fruits, flowers and vegetables show diseases caused by specific microorganisms that generate large postharvest losses. The degradation capacity of some phytopathogenic fungi could be useful to treat organic wastes, for instance in a pre-composting process. The objective of this study was to evaluate the capacity ofColletotrichum sp., Rhizopus sp. and Colletotrichum sp. + Rhizopus sp. to degrade ‘Paraiso’ mangoes, andRhizopus sp., Penicillium sp. and Rhizopus sp. + Penicillium sp. to degrade ‘Valencia’ oranges. In both cases eight treatments were prepared, where six treatments of whole and chopped fruits were inoculated by spraying a solution of fungi (3.5 x 106 spores mL-1). All treatments were prepared by triplicate; the experimental unit consisted of three fruits. Five parameters were recorded daily during 33 days (weight loss, pH of leachates, leachate production, incidence and severity of damage). Results showed the greatest weight loss and highest leachate production in chopped mangoes and oranges inoculated with a mixture of fungi. Incidence and severity were greatest in mangoes inoculated with Colletotrichum + Rhizopus. It was concluded that degradation was greater in mangoes and oranges inoculated with a mixture of Colletotrichum and Rhizopus,and Penicillium and Rhizopus, respectively. Thus, mixtures of fungi appear to have great potential for use in the pre-composting process. Key words: Fruit degradation, postharvest losses, leachates, solid waste.