Aim of the study: A total of 27 ethanolic plant extracts from 27 species were screened for leishmanicidal activity in vitro against Leishmania amazonensis. Most of the selected species (19) are traditionally used by the Chayahuitas, an Amazonian Peruvian ethnic group, to treat skin affections and/or leishmaniasis. Material and Methods: A colorimetric method based on the reduction of tetrazolium salt (MTT) was used to measure the viability of Leishmania amazonensis promastigote and amastigote stages. Results and Conclusions: Only the leaves of two species of the Piperaceae family (Piper hispidum Sw., and Piper strigosum Trel.) showed good leishmanicidal activities (IC50 < 10 μg/ml against amastigotes). Roots of Tabernaemontana sananho Ruiz & Pav. (Apocynaceae), together with bark of Vismia tomentosa Ruiz & Pav. (Clusiaceae), fruits of Solanum straminifolium var straminifolium Jacq. (Solanaceae), and stems of Zamia lindenii Regel ex André (Cycadaceae) showed low activity against amastigote stage (IC50 around 50 μg/ml). Of those only Tabernaemontana sananho displayed also good activity on promastigotes (IC50 < 10 μg/ml). Results are discussed herein, in relation with the traditional use of the plants and compared with other data from the relevant literature. © 2007 Elsevier Ireland Ltd. All rights reserved.