A new record of the freshwater jellyfish Craspedacusta sowerbii in northern Chilean Patagonia is reported. The specimens were collected from Laguna Illahuapi, an oligotrophic shallow lake (15 m maximum depth) in early austral autumn, May 2013. This water body is located in the upper zone of the Rio Bueno basin, Province of Ranco, Region de los Ríos, Chile. The region is characterized by a great diversity of freshwater environments with minimal human pressure. This report confirms the presence of C. sowerbii in Chilean Patagonia and represents the southernmost range of distribution of this exotic medusa in South America. This study also contributes additional information on the limnological characterization of this water body.