We describe a computer program for stereotactic surgery planning based on multimodality imaging and the display of intracranial EEG data in relation to anatomical data. The program is primarily designed to be used by surgeons to assist them in localizing brain structures and plan the safe and accurate insertion of surgical tools and depth electrodes. The mathematics underlying these concepts are briefly described. Estimates of the accuracy of the procedures are calculated and made available to the user. An extension of the program was developed to integrate intracranial EEG data with conventional images in order to help the neurologist and neurosurgeon in visualizing the EEG data in relation to the anatomy. It can be used to visualize the measured EEG voltages, or processed signals such as the application of the tetrahedral field calculation, which provides an extension of conventional bipolar EEG to 3 dimensions.