L. monocytogenes is commonly found in the environment. This bacteria gives rise to very wide range of symptoms in human. There are eight species of Listeria, L. monocytogenes is the significant human pathogen. In human listeriozis there is high rate of mortality and disease is largely confined to pregnant women, neonates and patients with underlying immunosuppresion. This article will deal with subpopulations most susceptible to infection by L. monocytogenes , the causative agent of listeriozis; symptoms and pathology the various form of listeriozis; means by which L. monocytogenes causes illness; transmission of L. monocytogenes to humans; and control of the disease.