A taxonomic study of Peltigera in South Korea was performed. The phylogenetic analysis based on nr DNA internal transcribed spacer sequences suggests that Peltigera is a well-supported monophyletic group. Important characteristics are the phycobiont type of thallus and the vein type at the lower cortex (wide and flat, or narrow and ridged). The vertical or horizontal arrangement of the apothecia is also important in distinguishing species in this genus. Eleven species of Peltigera were revealed and confirmed, which included one new record, P. elisabethae. A description of each species is presented with morphological, anatomic, and chemical characteristics, and comparisons between similar species are made. A key to the species is also presented.