The measurement of the body temperature in pigs is conventionally done by means of rectal temperature measurement using a thermometer. However, this is a time-consuming activity and in most cases, the method can hardly be put into practice feasible. Therefore, alternative methods for a reliable, fast and practical measurement of the body temperature are searched for. To evaluate the suitability of infrared thermometry, a method by which body surface temperature is recorded, an experiment was set up to assess whether it is possible to predict the rectal temperature based on the body surface temperature. Therefore, the body surface temperature of the ear, feet, side and anus was measured in 12 weaner pigs during 45 consecutive days. These temperatures were compared to daily-recorded rectal temperatures. The results clearly demonstrate that, although there is a significant correlation between most of the measured parts of the body surface temperature and the rectal temperature, no reliable predictions can be made for the rectal temperature. Therefore it can be concluded that infrared thermometry is not a good alternative for the detection of fever in pigs.