The dietary requirements of folivores affect many aspects of their ecology, including home range, potential for social interaction, abiotic/climatic requirements and habitat choice at the landscape and local scale. The purpose of this study was to investigate the advantages and disadvantages of three techniques commonly used to determine the diet of rainforest folivores. Many folivores are arboreal, nocturnal and cryptic, causing a variety of problems for determining their diet. The largely folivorous green ringtail possum (Pseudochirops archeri) is all of these, inhabiting complex rainforest and often displaying particularly cryptic or evasive behaviour. No single technique produced a comprehensive dietary list for P. archeri, and each had different biases in the diet composition determined. As the actual diet of P. archeri was unknown and not measurable, it was impossible to determine which technique most accurately described its diet. Direct observations were time-consuming and difficult within dense forest, faecal analysis underestimated the importance of species with fragile cuticles, and tree selection was not directly related to food intake. However, direct observation produced the highest diversity of diet from a single method, faecal analysis required the least time in the field, and tree selection allowed intraspecific measures of preference to be determined. Thus, multiple dietary analysis techniques were required to meet the aim of this study, which was to provide the most comprehensive estimation of dietary diversity in a cryptic, arboreal folivore.