in order to assess the use as growing substrate for the fungus pleurotus ostreatus, falling of the oak dead leaves in a forest relict in la capilla rural area, cajibio (cauca) was evaluated during 6 months, choosing mature trees with a chest height diameter (dap) between 35 and 37 cm were chosen, getting an average of 7,41 kg of dead leaves per tree. fungus growing in oak dead leaves mixed with sugar cane bagasse and 5 substrates: t1: bagasse 100%, t2: oak 100%, t3: oak 75% and bagasse 25%, t4: oak 50% and bagasse 50% and t5: oak 25% and bagasse 75% reaching biological efficiencies of 221,1%, 44,35%, 52,78%, 90,30% and 109,12% respectively. was an inverse association between the content of oak leaf and efficiencies due to the nature leathery and waxy leaf. most of the carpophores showed 5 and 12 cm and contamination caused by competing fungi of the trichoderma sp. genus. changes were detected in the depleted substrate composition, mainly minerals and protein increase and decrease of fiber in the bagasse and oak litter, being suitable for animal feed polygastric for mycelial protein content, presence of cellulose and lower lignin content.