The mycoflora of Korea was rather poorly studied in the past and the fungi belonging to the genus Septoria are no exception. For this reason, taxonomic studies on Septoria have been initiated, with the eventual aim of producing a monograph of the Septoria species present in Korea. The present study circumscribes 10 species; viz., Septoria artemisiae, S. callistephi, S. chrysanthemella, S. erigerontis, S. lycopersici, S. lysimachiae, S. oenotherae, S. phlogis, S. rohlenae, and S. sonchi. Distinguishing morphological characters are described and illustrated for each species.