Nilo-Saharan, a phylum spread mainly across an area south of the Afro-Asiatic and north of the Niger-Congo phylum, was established as a genetic grouping by Greenberg. In his earlier, continent-wide classification of African languages in articles published between 1949 and 1954, Greenberg had proposed a Macro-Sudanic family (renamed Chari-Nile in subsequent studies), consisting of a Central Sudanic and an Eastern Sudanic branch plus two isolated members, Berta and Kunama. This family formed the core of the Nilo-Saharan phylum as postulated by Greenberg in his The Languages of Africa, where a number of groups were added which had been treated as isolated units in his earlier classificatory work: Songhay, Eastern Saharan (now called Saharan), Maban and Mimi, Nyangian (now called Kuliak or Rub), Temainian (Temeinian), Coman (Koman), and Gumuz. Presenting an “encyclopaedic survey” of morphological structures for the more than 140 languages belonging to this phylum is impossible in such a brief study, also given the tremendous genetic distance between some of the major subgroups. Instead, typological variation in the morphological structure of these genetically-related languages will be central. In concrete terms this involves synchronic and diachronic observations on their formal properties (section 2), followed by an introduction to the nature of derivation, inflection, and compounding properties in Nilo-Saharan (section 3). This traditional compartmentalization has its limits because it misses out on the interaction with lexical structures and morphosyntactic properties in its extant members, as argued in section 4. As pointed out in section 5, language contact also must have played an important role in the geographical spreading of several of these typological properties.