The hydroconversion of cold lake vacuum residue (CLVR) in a semibatch, slurry-phase reactor was studied at 415-445 degrees C, 13.8 MPa, and a reaction time of 1 h, using MoS2 catalysts prepared from Mo-octoate and Mo-micelle precursors. Both precursors yielded MoS2 with the same activity in terms of coke suppression, residue conversion, and hydrogen uptake. The coke yield decreased from 22 wt % in the absence of a catalyst, to 4.8 wt % in the presence of 100 ppm Mo. A Mo concentration of 600 ppm was found to be optimum in terms of maximizing the residue conversion (84 wt %) and minimizing the coke yield (2.9 wt %). The characteristics of the recovered coke as a function of catalyst concentration and age in the reactor were also investigated. At high catalyst concentrations (>600 ppm Mo) and short reaction times, the generated coke was relatively amorphous, with a high H/C ratio. The solid catalyst-coke recovered from the reactor was recycled without further treatment. The catalytic activity of the recycled catalyst was the same as the fresh catalyst, and no catalyst deactivation was observed under the hydroconversion conditions of the present study.