The new radiation techniques are recently started to get more significance in the treatment of cancer. Electromagnetic hyperthermia is among the one of the prospective techniques. In this method the aim is to increase the temperature locally in cancer tissues by exposing them 30-60 minutes or more on electromagnetic radiation. The desired temperature range is 42-45 οC in cancerous cells while keeping the temperature in healthy tissues lower than 42 οC. Although within these temperature ranges it is not possible to kill the cancerous cells directly the intention is to cure it by damaging cancerous cell's protein build and change the cell construction. The accomplished investigations demonstrated that high temperature obstructs the cancerous cells evolution and even kills them. Since the cancerous cells dispositions are weaker than healthy ones the healthy cells near the cancerous cells are damaged lesser [1,2]. Another advantage of hyperthermia is since there is no toxicity it is appropriate to apply in conjunction with other treatment methods. The electromagnetic interaction calculations in human tissues is mostly realized by finite difference time domain method (FDTD) due to be suited for simulating nonhomogeneous models, scales well with the resolution increase, implicitly incorporates coupling between models and the antenna and can be implemented in hardware accelerator. From the calculated electromagnetic field values specific absorption rates can be calculated within the tissues. Finally by using of these values in Penne's bioheat equation the temperature distribution can be calculated. Depending to the results the therapy and the time can be determined. In this paper we presented the electromagnetic hyperthermia simulation of a human leg model in which the femur tissue is cancerous. We observed that by choosing properly the phase arrangement of the antenna system the focusing of fields is easily obtained and resulting an increase in temperature in the desired region. For the leg model the temperature is locally increased up to 42 οC in femur region while keeping other regions significantly at lower temperatures.