Crude oils are becoming heavier and their distillation processing yields heavier residues. The demand of high value petroleum products such as middle distillate, gasoline and lube oil is increasing. Therefore, the upgrading of heavy residues is an important process. We studied the hydroconversion of vacuum residue (VR) from REB (Russian Export Blend) crude oil in an autoclave. LCO (light cycle oil) or naphtha was added to the VR to study their influence to the reaction products. The analyses of the raw materials and reaction products were: dynamic viscosity; elemental analysis (%C, %N, %H, %S); density; GC of gases; solubility in hexane and toluene; simulated distillation; weight balance of solid, liquid and gas. In all cases, in the liquid product, the %wt. of hydrogen was higher, the %wt. of sulfur was lower and the nitrogen was removed (except when the naphtha was used as additive). The reaction using LCO had the highest liquid yield. The addition of naphtha resulted in an increment in the amount of heavier products in the gaseous phase (ethane, propane and butane).