• Temperatures were measured using an electronic thermometer in an emergency department to determine the relationship between oral or rectal and axillary measurements. A total of 164 data pairs were obtained—95 in afebrile children, and 69 in febrile children. The correlation coefficient was.74 for oral-axillary pairs, and.70 for rectal-axillary pairs. The mean difference between oral and axillary temperatures was 1.17°C ± 0.72°C, and between rectal and axillary temperatures was 1.81°C±0.97°C. Using 37.4°C (≥2 SDs) axillary as the upper limit of normal, the sensitivity, specificity, and positive and negative predictive values were calculated for detecting a fever. The sensitivity was 46%; specificity, 99%; positive predictive value, 97%; and negative predictive value, 72% for combined oralaxillary and rectal-axillary data. It was concluded that axillary temperatures are not sensitive enough to determine a fever when measured with an electronic thermometer. Electronic thermometers should be used to determine oral or rectal temperatures; axillary temperatures may be misleading and should be abandoned in the outpatient setting.