Interstitial hyperthermia techniques have been developed by several groups for use in a number of sites, especially those for which brachytherapy is to be given. Three basic methods have been developed for interstitial hyperthermia, namely: local current fields, microwave antennas and various hot-source techniques. In this paper a numerical study comparing two of these techniques (local current fields and hot sources) is carried out to investigate whether any improvement can be gained by combining them. It is found that both methods are sensitive to inter-electrode spacing and to blood flow, and become less able to produce adequate temperature distributions as these parameters are increased. By controlling the temperature of the electrodes it is shown that more uniform temperature distributions can be obtained over those obtained when the localized current field technique is used alone.