This review clearly states the classification of helminths and their mode of transmission in human-beings. Helminths are both hermaphroditic and bisexual species and classification is based on the external and internal morphology of egg, larval and adult stages. Generally, helminths are classified into three major types based on their external shape and the host organ they inhabit. They are Flukes (Trematodes); Tapeworms (Cestodes) and Roundworms (Nematodes). This review clearly describes the impact of these types of helminths and their mode of transmission on human-beings starting from children to adults. The classification and identification of helminths are dependent on numerous factors including body shape, body cavity, body covering, digestive tubing, sex and type of attachment organs. © 2021 World Research Association. All rights reserved.