The cold-smoked fish industry was used as a model for the development of a system for monitoring Listeriaspp. in foods and in the food processing environment. A total of 214 samples including raw fish, fish during the cold-smoking process, finished product, and environmental samples were collected from three processing facilities over two visits to each facility. Samples were screened for Listeriaspp. using the BAX for Screening/genus Listeriapolymerase chain reaction system (PCR) and by culture. Listeriaspp., confirmed by the API Listeriatest strip or by a PCR assay targeting the L. monocytogeneshlyAgene, were isolated from a total of 89 (41.6%) samples. Of these, 80 samples also tested positive for Listeriaspp. using the BAX system. Specifically, 42 (55.3%) environmental samples (n= 76), 11 (25.6%) raw materials samples (n= 43), 20 (35.1%) samples from fish in various stages of processing (n= 57), and 7 (18.4%) finished product samples (n= 38) tested positive for Listeriaspp. using the BAX system. Five (4.0%) of the 125 culture-negative samples yielded BAX system-positive results. Listeriaisolates from each of nine culture-positive/BAX system-negative samples yielded a positive reaction when tested in pure culture by the BAX system, suggesting that our false-negative results were likely due to the presence of low Listerianumbers in the initial enrichment as opposed to nonreacting isolates. The employment of alternative enrichment protocols, such as the two-step enrichment recommended by the manufacturer, may increase the sensitivity of the assay.