Both, taeniasis and cysticercosis are parasitic diseases caused by flatworms belonging to the class Cestoda (tapeworms), family Taeniidae, genus Taenia. The adult stages of Taenia species cause intestinal taeniasis in the definitive host whilst their larval stages or metacestodes (cysticerci) cause extra-intestinal cysticercosis in the intermediate host. Humans are the only definitive hosts for the intestinal adults of three Taenia species, namely Taenia solium Linnaeus, 1758 (the pork tapeworm), T. saginata Goeze, 1782 (the beef tapeworm) and T. asiaticus n. n. Eom et al., 2020 (syn. Taenia asiatica Eom and Rim, 1993) (the Asian Taenia). In addition to the adult stage, humans are also intermediate hosts for T. solium, consequently suffering not only taeniasis but also cysticercosis. T. solium was included in the World Health Organization (WHO) neglected tropical disease (NTD) roadmap in 2012 and this species is also the first on the list of the top 10 foodborne parasites elaborated by the Food and Agriculture Organization in 2014. Other mammals involved in the three Taenia life cycles are pigs as intermediate hosts of T. solium and T. asiaticus, and cattle in the case of T. saginata. Cysticerci of T. solium have also been molecularly confirmed in dogs and bears. A strain of T. saginata uses reindeer (Rangifer tarandus) instead of bovids as intermediate hosts in northern Russia. There are other Taenia species also causing human cysticercosis (T. crassiceps or T. martis for instance), although these are only sporadically reported. It has been suggested that T. asiaticus could also cause human cysticercosis, but there is no clear evidence so far. This chapter updates morphological, epidemiological and clinical data on taeniasis and cysticercosis, as well as methods of diagnosis and control of both parasitic diseases.