Forty mounds of the termite Cornitermes cumulans (Kollar, 1832) (Isoptera, Termitidae)were used to compare the efficiency of the following insecticides: A)fenthion (5% dust. 20g) ; B) and C) fenthion 50% EC (5cm³ and 2.5 cm³ in I ter of water, respectively); D) granular dodecachlor (0.45% bait, 40g).. The quantities indicate the material used inside each nest. Each treatment had 10 termite nests. Insecticides we re applied into the mounds through a canal made at the top of the nest with a steel bar. The best results were obtained with fenthion (B) , do decachlor bait (D). and fenthion (C).