In Niger, two communities, a urban one (Maradi) and a rural one (Tarna), living in a same malarious Soudano-Sahelian climatic area, were compared during wet and dry seasons by different methods (spleen rate, parasite rate, parasite count, level of immunity). During wet and dry season, spleen rates (0.7% and 2.6%) and parasite rates (1% and 1.6%) are considerably lower at Maradi than those observed at Tarna (spleen rates: 38% and 42%; parasites rates: 10% and 22.5%). It is shown that seroconversion occurs later in urban sector (100% between 20 and 29 year age) than in rural sector (100% between 10 and 15 year age). All malarious indicators were negative in a high percentage of Maradi-born children under 9 (79% during wet season and 81% during dry season) against respectively 28% and 31% at Tarna. Better paludometric index in urban community is a favourable sanitary indication. But epidemiological control must be prosecuted since the number of non-immune subjects is increased.