The effect of reaction temperature in the hydrocracking of Maya crude oil using a slurry-phase reactor was studied. The results indicate that the product distribution is clearly affected by the reaction temperature. In general, the transformation of heavy Maya crude oil into lower fractions follows a parallel-consecutive reaction scheme where vacuum residue converts to smaller fractions, and these fractions in turn, in a consecutive reaction path, are transformed to even lower liquid fractions and gases. Naphtha is the main product and does not seem to contribute significantly to the formation of gases. Solids appear to be formed by two main contributions: coke formation induced by thermal cracking, and precipitation of asphaltenes and other polycondensed aromatics. The precipitation of solids also seems to induce the elimination of sulfur and nitrogen compounds presents in the liquid phase. Increasing catalyst concentration from 300 ppm Mo to 1000 ppm Mo decreases the amounts of solid and gases, and increases liquid yield. (C) 2013 Elsevier B.V. All rights reserved.