Despite its central importance to tropical forest conservation, the understanding of patterns in traditional resource use still is incipient. To address this deficiency, we compared known palm uses among two indigenous (Yawanawá and Kaxinawá) and two folk (rubber tapper and ribeirinho) communities in Southwestern Amazonia (Acre, Brazil). We conducted one-hundred-and -forty semi-structured “checklist” interviews about palm uses with male and female adults in the four communities. The knowledge of each community about the uses of the 17 palm species common to all communities was compared by testing for significant differences in the mean number of uses cited per informant and by calculating the Jaccard similarity index of known uses of palm species among the four communities. The following three hypotheses were confirmed: 1) the use of palms differs according to the cultural preferences of each community; 2) indigenous communities know significantly more about palm uses than folk communities; and 3) part of the indigenous knowledge was acquired through contact with Amazonian folk communities.