One hundred and three strains of Listeria monocytogenes(Lm), Listeria seeligeri and Listeria innocua of clinical, food, and environmental origin were examined by generating randomly amplified polymorphic DNA (RAPD). Using one 10 bp and two 13 bp random primers, epidemiologically related strains, previously shown to be indistinguishable by phage typing, yielded identical RAPD profiles. Strains isolated from the hands of three workers in a retail food establishment showed the presence of a single predominant Lm isolate. RAPD analysis is a rapid, reproducible, and relatively inexpensive method for the differentiation of epidemiologically linked isolates of Listeria spp.