The findings of recent epidemiological surveys regarding the distribution of helminths in sheep, cattle, and buffaloes in central and southern Italy show that the presence of water in breeding, such as streams, canals, brooks, rivers and lakes, is a risk factor for the following helminths, agents of emerging zoonosis: Fasciola hepatica, Dicrocoelium dendriticum, Trichostrongylus spp., Ostertagia spp., Nematodirus spp., Haemonchus spp., Bunostomum spp., and Oesophagostomum spp. The Authors report up-to-date data on the distribution of the above cited helminths, as well as their essential morphological and biological characteristics and their zoonotic role.