Lipoptena deer keds (Diptera: Hippoboscidae) are blood-sucking ectoparasites of mammals, and only one species, Lipoptena cervi (L.), has previously been reported from the Republic of Korea. A study of Siberian roe deer Capreolus pygargus Pallas on Jeju Island, south of the Korean mainland, led to the discovery of a second species of deer ked, Lipoptena fortisetosa Maa, for Korea. In total, 518 deer keds were collected from 19 adult and juvenile deer examined from May to October 2012. The infestation of all of the deer examined and the occurrence on newly born deer suggest a high prevalence and abundance of L. fortisetosa parasitizing Siberian roe deer throughout Jeju Island. This deer represents a new host species for L. fortisetosa.