Background: Rectal route is a gold standard method of measuring fever, but it is invasive and stressful for parents and children. A recently used method is tympanic that has the advantages of safety, speed and compatibility but its accuracy is under question. Methods: In order to assess the accuracy of tympanic thermometry, 220 children within 3 months to 6 years old were selected and temperature was checked by rectal, axillary and tympanic methods. Results: The mean rectal temperature, compared with tympanic and axillary, was higher (0.3oc and 0.1oc, respectively). There was a good correlation between right and left tympanic measurements (r=0.87, P