Hyphessobrycon langeanii was originally described as endemic to the upper Araguaia river basin, Brazil. However, our analysis of several Hyphessobrycon specimens collected in the Correntes river basin and another tributary of the Itiquira River in Mato Grosso state (both belonging to the Paraguay river basin) reveals the first verified record of H. langeanii from this basin and from the states of Mato Grosso do Sul and Mato Grosso. The objective of this study is to provide a novel record of H. langeanii from the basin of the Paraguay River and from the state of Mato Grosso do Sul. We compare the newly discovered populations with the populations in the Araguaia river basin, and we also provide a brief discussion on the biogeography of this species.