Aims: Screening and partial characterization of a bacteriocin produced by Pediococcus pentosaceus K23-2 isolated from Kimchi, a traditional Korean fermented vegetable. Methods and Results: A total of 1000 lactic acid bacteria were isolated from various Kimchi samples and screened for the production of bacteriocin. Pediocin K23-2, a bacteriocin produced by the Pediococcus pentosaceus K23-2 strain, showed strong inhibitory activity against Listeria monocytogenes. The bacteriocin activity remained unchanged after 15 min of heat treatment at 121 degrees C or exposure to organic solvents; however, it diminished after treatment with proteolytic enzymes. The bacteriocin was maximally produced at 37 degrees C, when the pH of the culture broth was maintained at 5.0 during the fermentation, although the optimum pH for growth was 7.0. The molecular weight of the bacteriocin was about 5 kDa according to a tricine SDS-PAGE analysis. Conclusions: Pediococcus pentosaceus K23-2 isolated from Kimchi produces a bacteriocin, which shares similar characteristics to the Class IIa bacteriocins. The bacteriocin is heat stable and shows wide antimicrobial activity against Gram-positive bacteria, especially L. monocytogenes. Significance and Impact of the Study: Pediocin K23-2 and pediocin K23-2-producing P. pentosaceus K23-2 could potentially be used in the food and feed industries as natural biopreservatives, and for probiotic application to humans or livestock.