Listeria monocytogenes is a ubiquitous organism which presents challenges in controlling and monitoring the pathogen in the frozen food industry. This research was focused on understanding the prevalence of Listeria spp. and L. monocytogenes in the frozen food processing environment and on raw vegetables used in these facilities. The first activity was a survey of the frozen food industry to understand the design of processing facilities and their environmental monitoring practices. Listeria spp. sampling was most commonly performed weekly on non-food contact surfaces, with floors, drains, and walls as areas with the highest frequency of positive sampling sites. Subsequently, data was collected using a triple-blinded method that provided a safe harbor for collection of sensitive information from industry participants. Environmental monitoring observations from 27 facilities provided 42,799 results for Listeria. Zones 3 and 4 had a higher probability of having Listeria positive sampling sites compared to zone 2 for routine environmental monitoring samples. The most prevalent Listeria positive sites within a facility were drains (4.0%), pumps (3.9%), troughs (3.6%), chutes (2.5%), and containers (2.3%). The last activity determined the prevalence of Listeria spp. and L. monocytogenes on raw vegetables arriving at frozen food facilities. A total of 290 samples were collected, with 96 and 17 samples positive for Listeria spp. (33.1%) and L. monocytogenes (5.9%), respectively. Enumeration data for the 96 Listeria spp. samples indicated 82 samples had greater than 100 MPN Listeria spp./g and 14 samples less than 100 MPN Listeria spp./g. The Listeria prevalence on raw produce and in processing environments provides industry information that can be used for more accurate quantitative risk assessments for controlling Listeria in frozen food facilities.