1. Miniature temperature-sensitive radiotransmitters were implanted surgically into eighteen adult diamond pythons and thermoregulation of these snakes studied in a large thermal gradient in the laboratory. 2. Unfed diamond pythons selected temperatures in the range 26-33°C. Selected body temperature changed after feeding, with mean temperatures generally increasing by 2-5°C, and variances decreasing significantly in most snakes. 3. Selected body temperatures in the laboratory were similar to maximum body temperatures achieved when basking in the field. 4. Pythons without access to a heat source showed no elevation in body temperature after feeding indicating that the thermophilic response to feeding in this species is achieved behaviðrally, not physiologically.