The thermal needs of early weaned pigs were examined by placing pigs that were weaned from 13 to 16 days in indirect calorimeters and exposing them to four different temperature regimes. Pigs, in groups of ten (3 ft. 2 /pig), were weaned into four chambers at 88, 84, 80, and 76 o F and the temperature decreased by 2 o F per week for three weeks post-weaning. The feed efficiency and average daily gain during the three week trial for the four chambers were 1.30, 0.79 lb./day; 1.33, 0.84 lb./day; 1.38, 0.81 lb./day; and 1.27, 0.81 lb./day, respectively. Overall feed efficiency was significantly different between some of the treatments but average daily gain was not (P