In September 2018, an outbreak of Listeriosis cases in Korea was traced to food involved, using retrospective cohort studies and PFGE analyses. This study aimed to describe the first L.monocytogenes outbreak identified in Korea. We confirmed the presence of Serovar (4C) and virulence genes, and evaluated the genetic correlation between isolates by restriction digestion patterns of ApaI and AscI. Based on the epidemiological association, it is presumed that the seasoned crab meat with bean sprouts are contaminated by cross contamination during the bean sprouts washing (relative risk was 1.24; p-value: 0.0021 and they possessed virulence genes. Therefore, active laboratory surveillance is necessary to recognize the risk of L. monocytogenes in Korea.