The goal of this investigation is to develop and implement a numerical simulation model to predict the outcome of the thermochemical ablation therapy of tumors and other dysfunctional tissue. The simulation model formulated here includes a reaction zone whose volume is defined by the volume of the chemical reagents and a surrounding volume of tissue to be necrosed. Account is taken of the relevant macroscopic thermal processes of conduction, perfusion, metabolism, and internal energy storage/depletion. The zone of necrosed tissue is quantified by means of the Henriques-Moritz thermal damage integral. The simulation model was confirmed by comparisons with available experimental data. The main results extracted from the simulations are the temporal and spatial temperature variations throughout the tissue bed and the resulting distributions of necrosed and non-necrosed tissue. The radius of the zone of necrosis was algebraically correlated with the heat of reaction of the participating reagents. It was demonstrated that through the selection of appropriate conditions, sufficient thermal energy can be released to ablate significant volumes of tissue. The duration of the treatment required to achieve a pre-selected zone of necrosed tissue can also be predicted.