To evaluate the accuracy and consistency of tympanic temperature measurement in children.A correlational study compared tympanic temperature measurements with oral, axillary, and rectal measurements. A convenience sample of 209 hospitalized children ages newborn to 12 years was stratified according to age. Cross tabulation by fever was analyzed for sensitivity and specificity.Tympanic measurements were significantly correlated to oral, axillary, and rectal measurements. The correlation between axillary and tympanic in newborns was lowest. Tympanic measures identified fevers more often than oral or axillary measurements when compared to rectal measurements.Tympanic measurement in newborns was not sufficiently accurate. Tympanic measurements may be used routinely in children older than 3 years.