Studies were conducted which examined the effects of radio frequency (RF) radiation on heart rate (HR), deep body temperature (TEMP), and electrocardiographic (ECG) waveform parameters in anesthetized rats. One group of animals was exposed to two power levels of continuous wave RF radiation averaging 1.0 and 7.4 W/kg at a frequency of 600 MHz. A second group of animals, treated identically but not exposed to RF radiation, served as a control. The electrodes used to monitor the ECG during RF exposure were fabricated using carbon-loaded Teflon wire, a semi-conductor material that does not perturb the RF field. Analyses of the ECG were conducted using a recently developed computer-assisted procedure which quantitates HR and waveform intervals over 25-40 individual ECG complexes. There were no artifacts or arrhythmias in the ECGs of the animals exposed to RF radiation. There was a significant linear correlation between HR and TEMP in the RF-exposed group which was not present in the control group.