The Clackamas County Sheriff's Office says at least two people were killed at the Clackamas Town Center.
One witness says a man wearing a hockey mask and holding a rifle opened fire inside the crowded mall.
Ten ambulances were called out to help those injured.
Another victim was injured and police say the suspected gunman is dead.
Oregon Governor John Kitzhaber released a statement saying state police are on the scene and will make "all necessary resources available to local law enforcement."