Listeria monocytogenes is a food-borne pathogen present in various environmental reservoirs. It exhibits resistance and tolerance to antibiotics and sanitizing agents used in several food processing industries. It has been reported that L. monocytogenes chitinase can catalyze hydrolysis of chitin polymeric carbohydrate present in the environment and act as a virulence factor that support its survival in mammalian host cells. By taking advantage of chitinase, L. monocytogenes has both saprophytic and pathogenic lifestyles in the soil and the living host, respectively. The objective of the present study was to determine the involvement of chitin degradation products such as chitooligosaccharides (COS) in biofilm formation of L. monocytogenes. Results showed that different concentrations of COS with various molecular weight enhanced biofilm formation of L. monocytogenes. Such enhancement in biofilm formation contributed to the development of antibiotics resistance and disinfectants tolerance of cells present in the biofilm. The present article also described diverse roles of chitin, chitinase, and degradation of chitin and chitin-like substrates in saprophytic and pathogenic lifestyles of L. monocytogenes. This study offers a new direction for further exploration of the mechanisms of pathogenesis caused by L. monocytogenes. Copyright © 2019 Elsevier Ltd. All rights reserved.