Here we describe five new North Eastern Pacific species of acorn worms in the genus Saccoglossus (S. porochordus, S. rhabdorhyncus, S. shumaginensis, S. sonorensis, and S. palmeri) on the basis of morphology. Notes on the habit and localization of each species are provided. A summary table lists the morphological characters defining the five new species and ten previously described ones in the genus Saccoglossus. Observation on the biogeography of Enteropneusta suggests that it is an ancient and declining group.