Vegetable trimming residues are very plentiful and diverse; however, their recycling involves environmental problems. Producing high quality compost from these residues is a way to make a good use of them. The present work studies the influence of the operating conditions used during a composting process of vegetable trimming residues (aeration, moisture, particle size, composting time), on the evolution of the temperature, pH and CO2 while the compost is producing and on the physicochemical properties of the final compost (pH, organic matter, Kjeldahl-N, C/N ratio). An adaptive network based fuzzy inference system on basis of the four considered independent variables (aeration, moisture, particle size, composting time) was used to obtain the optima composting conditions which produce the best pH, temperature and CO 2 evolution and the highest quality compost. Low aeration contents (0.2 Lair (min kg-1), intermediate moisture content (55 %), medium-to-low particle size (1-3 cm) were the best operating conditions to obtain maximum temperatures and CO2 production. Moreover, under these conditions, it was obtained compost with satisfactory physico-chemical properties, useful for further agricultural application. © Springer Science+Business Media B.V. 2012.