Abstract Chimpanzees of Kasoge use tools in the trees for collecting arboreal ants ( Camponotus spp.) mostly in woodland vegetation. Ant-gathering by the use of tools is routine behaviour, at least during the first half of the rainy season. Three kinds of tools were recognized: wiping handkerchief, expelling stick and poking rod. Although the first two types were observed only once, this is the first time that these methods of using plants to obtain insects have been recorded. The poking rods can be divided into five categories which differentiate between the materials used and the way and the degree to which these materials are modified. The use of a mid-rib of the leaf as a rod is a modification peculiar to a chimpanzee of Kasoge. The apparent selectivity of the plant species as the material for a tool was made clear, with special reference to the ethnobotany of the sympatric Batongwe tribe. The tool-using activity of “chimpanzee level” does not require the exclusive specialization of one hand. Ant-gathering was seen during the time when chimpanzees usually take a rest between the two intensive feeding periods of a day. This implies that ant-gathering by use of tools is a kind of luxury.