PURPOSE: The presence and degree of fever in children is a useful indicator of illness. This project aimed to assess the accuracy and usefulness of infrared tympanic membrane (TM) & forehead feverscan thermometers for measuring children's temperatures. METHODS: Data were obtained from 1, 050 children with a median age of 4.5 years. They visited the pediatric clinics at Chung-Ang University Yongsan Hospital from January 2004 to December 2004. We measured body temperatures at axilla by mercury thermometer, at ear by infrared TM thermometer and at forehead by feverscan. Then we analyzed the correlation between these data. RESULTS: Mercury and TM thermometer, and Mercury and forehead feverscan thermometer very well correlated with each others (P< 0.05). And the sensitivity of infrared TM thermometer (right and left) to correctly identify febrile children was 81.1 percent and 82.4 percent, the positive predictive value to detect a fever was 81.8 percent and 73.6 percent. The sensitivity of forehead feverscan was 83.3 percent and the positive predictive value was 74.4 percent. CONCLUSION: The tympanic membrane temperature measured by the BRAUN IRT 3020 (R) and forehead arterial temperature measured by the HubDIC DOTORY (R) feverscan accurately reflects mercury axillary temperature, validly assesses the presence of fever in children, and is easy to use. The Braun IRT 3020 (R) & HubDIC DOTORY (R) therefore is an adequate tool to assess fever and may be used both in a clinical setting and for research purposes.