At present, a successful realization of the magnetic fluid hyperthermia (MFH) therapy is conditioned by some unsolved problems. One of these problems is the choice of the correct particle concentration in order to achieve a defined temperature increase in the tumor tissue. A computer-based model was created using COMSOL: Multiphysics in order to simulate the heat dissipation within the tissue for typical configurations of the tumor position in relation to neighboring blood vessels as well as particle distribution within the tumor. The temperature achieved on the tumor border was investigated taking into account physiological parameters of different types of tissues. Using the correct nanoparticle dosage and considering their specific loss power, it is possible to estimate the efficiency of this therapeutic method. If the tumor shape and position are known by suitable medical imaging techniques (e.g., MRI, CT), simulations like this one could provide data in order to achieve the optimum dose and particle distribution in the tumor.