Abstract: The seahorse Hippocampus patagonicus (Teleostei: Syngnathidae) is the southernmost occurring species of its genus in the South Atlantic Ocean. Its distribution seems to be restricted to the Southwestern Atlantic, along the coasts of Argentina and Brazil. Herein we report the incidental capture of six individuals as bycatch in the shrimp trawl fishery off the coast of Paraná, southern Brazil. Additional information on the geographic distribution of H. patagonicus, together with its ecology and life history, is important for conservation of this threatened species. These data can promote the development of appropriate management and conservation strategies for populations along the Brazilian coast.