A study of preserved starch grains from sedimentary sequences at Niah Cave, Sarawak, Borneo, reveals direct evidence for the use of rainforest plants rich in digestible carbohydrates. Plants identified include several species of Aroids (Alocasia sp., Cyrtosperma sp.), at least one species of yam (Dioscorea sp.), and the pith of sago palm (cf. Caryota mitis, Eugeissona utilis). Starch grains from a total of fourteen recurring types indicate that a wide range of starch-rich plants are present in Pleistocene occupation sediments from the cave, and await identification with a more comprehensive reference collection of tropical species. The technique of starch extraction from archaeological sediments presents archaeologists with a new and powerful tool for investigating the past diet of tropical forest hunter-gatherers.