Millions of people in in rural areas and deprived tropical and subtropical regions are infected by soil-transmitted helminths: Ascaris lumbricoides, Trichuris trichiura, hookworms (Ancylostoma duodenale and Necator americanus), and Strongyloides stercoralis. Large migratory flows have made their worldwide distribution easier. Besides being debilitating and producing a significant mortality, they cause high morbidity, leading to physical and intellectual impairment in millions of children who live in poverty. Along with the use of benzimidazoles (albendazole and mebendazole), large-scale international campaigns for treatment and prevention have decreased the number of affected individuals. However, re-infestations and benzimidazole-resistance are frequent, so there needs to be awareness about the importance and consequences of these neglected parasites.