Abstract: We report range extensions for three species of Amazonian erethizontids, Coendou bicolor, C. ichillus, and C. nycthemera. We record C. ichillus for the first time in Brazil, from Rio Japurá, state of Amazonas. We record C. bicolor for the first time in the state of Amazonas, which represents a range extension of approximately 905 km. We also extend the occurrence of C. nycthemera 620 km to the south into Mato Grosso state. All records are based on museum specimens, highlighting the importance of scientific collections as biodiversity databases and emphasizing the lack of research on Amazonian porcupines.