Background/Question/Methods The Matschie's tree kangaroo (Dendrolagus matschiei) is an endangered species endemic to the Huon Peninsula of Papua New Guinea. The Tree Kangaroo Conservation Program, now in its tenth year, is a multidisciplinary and multinational program to save this flagship species from extinction. Part of the conservation effort is to determine the diet of wild tree kangaroos, to ensure land pledged by local landowners contains D. matschiei food plants. This project was concerned with determining diet through microhistological analysis of wild-collected fecal pellets. Plant fragments in the pellets were identified through investigation of the cuticle, the waxy coating on the outside of the leaf. The cuticle takes an impression of the epidermis below it and this pattern can be used to identify plant fragments to the genera or species level. Although an established technique for captive animals, this is one of the first times microhistological analysis of plant cuticle has been used to determine diet for wild animals. D. matschiei can feed on up to 40 different families of plants making microhistological analysis of their fecal pellets more challenging than for captive animals. Results/Conclusions We will present the methods we have developed to create a library of reference slides of cuticles of known rainforest species and we will show that it is possible to process the egesta and retrieve usable samples. Preliminary results reveal matches between plant cuticle in the reference collection and cuticle fragments processed from the fecal pellets. Our preliminary success suggests that microhistological analysis of wild D. matschiei pellets is a technique that may be used to analyze diet in cryptic wild species, with important applications for in situ conservation.