This chapter consists of short notes, diagrams, maps, and tables to summarize human nematode (‘roundworm’) infections, starting with a classification of relevant organisms. The chapter then goes on to cover Ascaris, Trichinella, Enterobius (‘pin worm’), Trichuris (‘whip worm’), Necator and Ancylostoma (‘hook worms’), and Strongyloides (‘thread worm’). The chapter concludes with a section dedicated to filarial infection, including lymphatic filariasis, Loa Loa (‘eye worm’), Onchocerca volvulus (‘river blindness’), and Dracunculus (‘Guinea worm’). For ease of reference, each topic is broken down into sections, including classification, epidemiology, microbiology, pathophysiology, clinical syndromes, diagnosis, treatment and prevention.