Fumigation with methyl bromide at a dosage of 2.5 pounds per 1, 000 cubic feet for 15 to 19 hours apparently eliminated all natural infestations of the dry-wood termite, Cryptotermes brevis (Walker), within 23 of the 24 buildings fumigated. However, considerable differences occurred in mortality among the termites exposed in wooden block cages exposed in 18 building fumigated with this gas was: 6 buildings 100per thousand, 4 buildings 91per thousand to 99per thousand, 3 buildings 51per thousand to 90per thousand, 3 buildings 11per thousand to 50per thousand, and 2 buildings 0per thousand to 10per thousand. On the other hand, sulfuryl fluoride at a dosage of 2 pounds per 1,000 cubic feet for as little as 1.5 hours killed all the termites in similar blocks. Ethylene dibromide at 2 to 3 pounds per 1, 000 cubic feet for 24 hours failed to penetrate the wooden block cages in sufficient quantity to cause any measurable mortality. Furthermore, fumigation with this gas failed to eliminate the natural infestations in two out of five treatments. It is apparent from these test that sulfuryl fluoride (eight buildings fumigated in tests) was far superior to methyl bromide and methyl bromide was far superior to ethylene dibromide. The use of sulfuryl fluoride should make it possible to greatly reduce exposure time, a great asset in the fumigation of buildings.