Natural history collections are an important source of data for a wide range of studies, including geographic distribution changes (spatial or elevational), extinctions, biological invasions, endangered species, evolutionary processes (morphometrics and genetics), and anatomical comparisons. One of the lesser-known natural history collections from Ecuador is that of the Laboratorio-Museo de Zoología Gustavo Orcés (LMGO), located on the sixth floor of the Facultad de Filosofía, Letras y Ciencias de la Educación at Universidad Central del Ecuador. The main objective of this paper was to catalog and identify all the mammal species deposited in the LMGO as well as analyze the existing geographic records for two species. We compiled all the information found on the original labels of each specimen and used several field guides to confirm specimen identification. Likewise, all the localities recorded for each species were plotted on a map. The LMGO holds 203 specimens representing 14 mammalian orders, 38 families, 71 genera, and 94 species. Of the 94 species, 87 are native (including two endemic and one domesticated); the remaining include two exotic, two invasive, and three introduced domestic species. Our analysis provided notable records for two species, Nephelomys nimbosus and Cuniculus taczanowskii, a conclusion based on a review of all records available in the literature or in digital biorepositories for those species. The Universidad Central del Ecuador has additional natural history collections that have never been reviewed formally. We suggest a review of these collections with the objective of finding other noteworthy records for rare or endangered mammals.