Investigations in the laboratory and field in the United States on the use of heat to eliminate structural and other pests in buildings are described. The time (in minutes) required to cause 100% mortality in adults of Blattella germanica, Tribolium confusum/<sun the laboratory ranged from 7, 4, 1, and 6, respectively at 54° C to 58, 123, 8, and 265 at 46° C. The results are presented of experiments in which temperatures in about this range were applied in a simulated building (against the same pests, including I. minor in structural timbers, and adult and immature stages of the flea * 2Ctenocephalides felis*1). Compared with wood-infesting insects, free-living insects were killed very rapidly. In field studies in buildings in California, heat treatments are described that controlled I. minor in timbers, and the ant <i>Camponotus clarithorax</i> (<i>C. caryae clarithorax</i>) in a kitchen area. In Hawaii, <i>Cryptotermes brevis</i> was controlled in structural timbers and furniture. -- AATA