The role of the pineal gland in diet-induced thermogenesis (DIT) and growth of brown adipose tissue (BAT) in rats during voluntary overfeeding was studied using pinealectomized and sham-pinealectomized rats. Overfeeding was induced by offering the animals a cafeteria-diet (CD) which contained a selection of highly palatable food items. Rats which were fed CD had significantly increased interscapular brown adipose tissue (IBAT) mass and increased tail-skin temperature indicating the importance of the tail in thermoregulation during DIT. Pinealectomy had no effect on the increase in tail-skin temperature and deposition of IBAT, which were stimulated by CD feeding. These findings suggest that the pineal is not directly involved in modulating the metabolism of BAT in rats.