The influence on malaria incidence in Algeria of anophelism in the oases and construction of a trans-Saharan highway is discussed. The few remaining cases of malaria in Algeria are of Plasmodium vivax, a parasite absent from tropical West Africa where P. falciparum, now eradicated from the Mediterranean Basin, predominates. Epidemics arising from imported falciparum malaria are considered to be unlikely in Algeria north of the desert, but some oases are at risk. More precise estimates of the probabilities of outbreaks in these oases require analyses of their populations of Anopheles sergentii s.l., a taxon comprising vector and nonvector forms, and also establishment of the northerly limits of the distributions in Niger of A. arabiensis and A. gambiae.