In the last few years, there has been an increase in outdoor pig production in many countries. Outdoor herds, on average, are still less productive than indoor herds, often due to higher pre-weaning piglet mortality. Hypothermia is one of the most important underlying causes of piglet mortality in early post-natal life (English and Morrison, 1984). Although the extent of hypothermia suffered by the new-born piglet in an indoor system has been demonstrated (Pattison et al, 1990), no data of this kind are available regarding the outdoor situation. The objectives of this study were to evaluate the extent of hypothermia suffered by outdoor piglets at 30 and 60 minutes after birth, and to compare this with piglets born indoors.