Peridiscus lucidus (Peridiscaceae) is recorded for the first time for the vascular flora of Colombia based on a collection from the upper Río Cuyarí, Guianía Department. This locality extends the northwestern distribution of the species in the Amazon basin to the upper Río Negro basin. Notes about the phytogeography and habitats of P. lucidus and an updated overview of the currently known specimens using a geographic distribution map of this taxon are also included. In addition, we provide information on the distinctive vegetative characters that help identify this genus in absence of flowers and fruits. Finally, a lectotype of P. lucidus is newly designated. The discovery of this family in the upper Rio Negro region of Colombia demonstrates the value of field work through alliances between private initiatives and the Kuripaco nation.