This study aims to assess the correlation between surface temperature estimated by infrared thermography and core temperature measured with rectal thermometer in weaning and fattening pigs. A total of 108 pigs were used in this study. Thermal images of the eye of each animal were recorded with a thermal imaging camera, rectal temperatures were measured using a calibrated digital thermometer. The average rectal temperature was 38.9 ± 0.4 °C (MIN = 37.9 °C; MAX = 40.1 °C) and the average eye temperature was 36.7 ± 0.1 °C (MIN = 34.8 °C; MAX = 38.8 °C). Our results showed that the mean eye temperature estimated by infrared thermography was significantly correlated (r = .581, P < .01) with rectal temperature. The correlation was significant and strong for weaners (r = .739, P < .01), significant although weak for fatteners (r = .236 P < .05). Thermography could be a valid method to estimate the core temperature of pigs under farm condition.