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). At birth, body weight and rectal temperature were recorded from piglets of the 11th generation of the low RFI (LRFI, more efficient; n=34) and the high RFI (HRFI, less efficient; n=28). 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 (SAS 9.4). All temperatures increased overtime. The 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 had higher minimum (28.0±0.16 vs 26.8±0.16 °C; P<0.001) and average (35.5±0.20 vs 34.5±0.13 °C; P<0.001) back temperatures than HRFI piglets. The interaction between line and time affected the temperature of the ear tip and the minimum back temperature (P<0.05), but pair-wise comparisons were not significant. However, ear tip temperature decreased in HRFI piglets between 8 and 15 min post-partum while it increased in LRFI piglets (-1.1±0.42 vs 0.5±0.45 °C, 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.