Hypothermia is a factor of piglet neonatal mortality. This study used Infra-Red Thermography (IRT) to assess thermoregulation abilities of piglets from two lines divergent for residual feed intake (RFI). Birth phenotypes (e.g. body weight, rectal temperature, physical measures, vitality test) were recorded from piglets selected for low RFI (more efficient; LRFI; n=34) or high RFI (less efficient; HRFI; n=28). The IRT images were taken at 8, 15, 30 and 60 min post-partum. Temperatures of the ear base and tip, and minimum, maximum and average temperatures of the back (i.e. shoulders to rumps) were extracted with Thermacam Researcher Pro 2.0 and analysed with linear mixed models. No difference in phenotypic data was detected between the two lines. All temperatures increased over time. Rectal temperature of piglets at birth was correlated with the initial temperature of the ear base and the maximum back temperature (0.36 and 0.35, respectively, P < 0.05). Overall, LRFI piglets, compared to HRFI piglets, had higher minimum (28.0 ± 0.2 °C vs 26.8 ± 0.2 °C, respectively, P < 0.001) and average (35.5 ± 0.2 °C vs 34.5 ± 0.1 °C, respectively, P < 0.001) back temperatures. Ear tip temperature decreased in HRFI piglets from 8 to 15 min post-partum, while it increased in LRFI piglets (-1.1 ± 0.4 °C vs 0.5 ± 0.5 °C, respectively, P < 0.05). In conclusion, IRT allowed non-invasive assessment of piglets’ thermoregulation abilities. Piglets selected for low RFI seemed to have better thermoregulation abilities at birth.