The Rondônia Natural Resources Management Project (PLANAFLORO) was a strategic program developed in partnership between the Brazilian Government and The World Bank in 1992, with the purpose of stimulating the sustainable development and protection of the Amazon in the state of Rondônia. More than a decade after the PLANAFORO program concluded, the aim of the present work is to recover and share the information from the long-abandoned plant collections made during the project’s ecological-economic zoning phase. Most of the material analyzed was sterile, but the fertile voucher specimens recovered are listed here. The material examined represents 378 species in 234 genera and 76 families of angiosperms. Some 8 genera, 68 species, 3 subspecies and 1 variety are new records for Rondônia State. It is our intention that this information will stimulate future studies and contribute to a better understanding and more effective conservation of the plant diversity in the southwestern Amazon of Brazil.