Over ten thousand cubic meters of tropical hardwood of Debema (Piptadeniastrum africarum Brenan), Ako (Antiaris africana Zngl.), and Frake (Terminalia superba Zngl. et. Diels), imported from Ivory Coast were damaged seriously by wood-destorying insects. The insects found in these damaged hardwoods were Bostrychidae, Platypodidac, Ipidae, Atractoceridae, Lycyidae and Curculionidae, most of which had never been observed in this country. Fumigation treatment was applied to ensure that these wood-destorying insects would not spread. Three fumigants, Chloropicrin (NOCC13), Methyl Bromide (CH3Br), and Sulfuryl Fluoride (SO2F2), were used in the test. The concentration of these three fumigants and the time of fumigation treatment were, in turn, 62.5g/m3 for 72 hrs, 50g/m3 for 60 hrs and 40g/m3 for 48 hrs. After the treatment, the mortalities of insects, including adults, larvae and pupae, were 73.4%, 100% and 100% respectively. In order to check the insecticidal effectiveness of fumigants, a production test of about 500m3 hardwood was conducted. In this test, only 60g of Sulfuryl Fluoride per cubic meter hardwood was used for 48 hrs. The mortality resulted was 100%. To achieve reliable control, excessive application of fumigant was advisable.