A finite-difference time-domain technique was used to calculate the specific absorption rate (SAR) at various sites in a heterogeneous block model of man. The block model represented a close approximation to a full-scale heterogeneous phantom model. Both models were comprised of a skeleton, brain, lungs, and muscle. Measurements were conducted in the phantom model using an implantable electric-field probe and a computer-controlled data acquisition system. The calculation and measurement of SAR distributions were compared primarily in the head (including the neck) and chest. To obtain the necessary spatial resolution with the computer model, the head and neck were modeled with approximately 105,000 cells, while 86,000 cells were used to configure the chest. Planewave fields, polarized in the E orientation, were utilized to irradiate the models at an exposure frequency of 350 MHz. Reasonable correlation existed between the calculations and measurements.