Type IV hyperlipoproteinemia is characterized by increased blood levels of the triglyceride form of the fat that makes up very low-density lipoproteins (VLDL). Eruptive xanthomas have been frequently observed in type I and V hyperlipoproteinemias but rarely observed in patients with type IV hyperlipoproteinemia. The Koebner phenomenon is the development of the isomorphic skin lesions in persons with certain skin diseases after an injury has occurred on skin of normal appearance. Although this response can develop in psoriasis, lichen planus, verruca etc., it has seldom been associated with eruptive xanthoma. We report a case of eruptive xanthoma with type IV hyperlipoproteinemia and Koebner phenomenon in a 28-year-old Korean male. (Korean J Dermatol 2008;46(6):784∼787)