The Brushtail possum ('Trichosurus vulpecula') is reported to eat vegetation, fruit, flowers, fungi and meat in the form of birds (e.g., starlings, blackbirds) and their eggs. However, this omnivorous behaviour and ability to adapt to a varying diet has not been investigated systematically. The first experiment involved a single stimulus preference assessment of possum's consumption of individually presented food items that included: meat, eggs, native foliage, fruit and invertebrates. The second and third experiments used paired stimulus assessment and concurrent schedule procedures to establish ranked preference and demand curves for these different food types. Results suggest that captive possums display similar opportunistic feeding behaviour observed in wild possums. Further studies will examine the development and influence of food choices by other possums on the transmission of taste preferences between possums. These studies may provide information relevant to maintaining captive populations of possums for behavioural research by contributing to the knowledge of methodologies compatible with possums and provide strategies and practices for the management of the pest problem in New Zealand.