The movements of Australian brush-tailed opossums, Trichosurus vulpecula, were studied in a mixed bush, scrub, and pasture habitat on Banks Peninsula by live-trapping and spotlighting over a period of six months from February to July 1971. Thirty-four opossums were marked. Estimates of the size of ranges in the pasture (0.8 ha males; 0.3 ha females) were smaller than those found elsewhere, probably because of the restricted habitat. Range sizes of animals resident in the bush were considerably altered by their movements" to seasonal food sources in the pasture. Male opossums did not hold territories as described in some studies. In this mixed habitat opossums may move between scrub, bush and pasture to obtain food and shelter.