The invention is directed to a method for determining a temperature by means of a radiation thermometer with multiple infrared sensor elements detecting infrared radiation from different regions and delivering corresponding temperature signals, in particular to a method for taking a patient's temperature by means of an ear thermometer. The method of the present invention is based on the known fact that the tympanic membrane has a higher temperature than the ear canal. Hence part of the sensor elements, that is, those that view the tympanic membrane, will detect a higher temperature than the remaining sensor elements that view the ear canal. According to the present invention, for evaluation only the temperature signal of that sensor element is used that supplies the peak temperature value by comparison with the other sensor elements.