The monito del monte (Dromiciops gliroides) is an arboreal marsupial found only in austral South American temperate rain forests. Its conservation is a priority as the only extant species of the order Microbiotheria. We investigated whether the apparent low abundances reported for D. gliroides are real, or reflect a sampling artifact. We used wire-mesh and Sherman live traps, devices for recording tracks and hair, 2 types of bait, and 2 trap placements (ground level and 1.5–2.5 m high) in an old-growth forest in southern Chile. Type of bait and placement height affected captures of D. gliroides. The most efficient trapping combination (wire-mesh traps baited with banana, and placed above ground) yielded capture rates of up to 11%, and a relative population density of 21 ± 5 individuals/ha (mean ± SE), whereas traditional methods used for sampling small mammals were not effective. The sampling artifact uncovered here may have important future management and conservation implications.