The removal of sulfur and hydrocracking reactions that occur during hydrotreatment of heavy oil were modeled by means of the continuous kinetic lumping approach. Distillation curves of feed and products were obtained with the true boiling point method. The sulfur curve was determined from the analysis of the different fractions recovered during distillation. Sulfur was almost totally removed from the light fraction, while the heavy fraction was concentrated with this impurity. A total of eight parameters were calculated to model both reactions (five for hydrocracking and three for hydrodesulfurization). The comparison of predictions with experimental data indicates good agreement in the entire distillation and sulfur curves.