In this work we report experimental information about the hydroprocessing of Maya heavy crude oil using two reaction stages. Experiments were performed in a high-pressure fixed-bed pilot plant. Hydroprocessing reactions were carried out at constant pressure (70 kg/cm(2)) and Hydrogen-to-oil ratio (5000ft(3)/bbl). Space-velocity and reaction temperature were varied in the ranges of 0.5-2.0 h(-1) and 360-400 degreesC, respectively. First reaction stage used a NiMo/Al2O3, while second stage employed a CoMo/Al2O3 catalyst. Experimental and characterization results show that Maya crude oil quality can be substantially improved by hydroprocessing in two reaction stages. Different behavior in heteroatoms (sulfur, nitrogen, asphaltenes, and metals) removals, hydrocracking (HCR), and pore size distribution of catalysts after reaction were observed in each reaction stage.