Genetic parameters of rectal temperature measured at 0700 and 1200 (RT7 and RT12), the difference between RT12 and RT7 (dRT), daily feed intake during ad libitum period in lactation (DFI), litter growth rate (LGR) and sow relative body weight loss during lactation (BWL) were estimated in the Large White lactating sows reared in a tropical humid climate. The h² were 0.28 ± 0.03, 0.32 ± 0.05 and 0.49 ± 0.14 for RT7, RT12 and dRT. The h² for DFI, LGR and BWL were low. Genetic correlations between thermoregulation and performance traits in lactation ranged from -0.63 ± 0.13 (between RT12 and LGR) to 0.87 ± 0.42 (between dRT and BWL).These preliminary results show the existence of genetic variability for thermoregulation.