Two experiments concerned with chemical control of tree suckers on Cockatoo sand were carried out in the Ord River valley, Western Australia, in 1961-62 and 1962-63. Suckers of Eucalyptus ferruginea Schau., Eucalyptus tetrodonta F. Muell., Erythophleum chlorostachys(F. Muell.) Baill. and Acacia mangium A. Cunn, were tested with 2,4-D, 2,4,5-T, monuron and fenuron. The results of these experiments showed that 2,4,5-T at 6 lb an acre active ingredient effectively controlled the above-ground vegetation of Eucalyptus ferruginea and Acacia mangium, partially controlled Eucalyptus tetrodonta, but was not effective in controlling suckers of Erythophleum chlorostachys. Monuron at 30-40 lb an acre active ingredient effectively controlled all of these species, with the exception of Erythrophleum.