Abstract This paper presents a comparative study of natural and mechanically mixed composting processes of marc resulting as a byproduct during the production of alcohol obtained from fermented fruits. Moisture, temperature, pH values, soluble fraction, total organic carbon, Kjeldahl nitrogen and ash content were monitored for 60 days. During this period the atmospheric temperature varied from 18Â?C to 21Â?C. The composting process could be considered a combination of three stages: mesophilic, thermophilic, and maturation. The composting process need 34 days in mechanical stirred system and 46 days in the natural system. The biodegradation processes were stimulated by the mechanical stirring.