Body temperature is a basic physiological measurement used primarily for observation and diagnosis during surgery, pandemic diseases, intensive care, recovery or treatment. Various thermometers are clinically used for these measurements and can be divided into two categories, contact or non-contact. To have maximum confidence in the clinical performance of the temperature measuring instrument, it is important to calibrate the instrument traceable to the 1990 International Temperature Scale (ITS-90). The absence of traceable calibrations accredited to ISO/IEC 17025 can lead to insecurity in temperature measurement and in some cases can have a detrimental effect on patient care.Infrared or radiation thermometers are preferred in many different sectors from health to food, from automotive to agriculture, from iron and steel industry to chemistry due to their fast measuring capabilities, reasonable prices, wide measuring ranges and ease of use. In this study, ear thermometer calibration and measurement uncertainty calculations are investigated by using the traceability method via contact thermometer. Considering the maximum permissible error value of the device, conformity assessment is made according to the measurement result.