While the proximal causes of drought in the Sahel and northeast Africa are known to be due to failure of seasonal rains, possibly linked with long-range climatic changes (Tanaka et al., 1975; Winstanley, 1973; Kelley, 1975; Lamb, 1977), the more persistent problem of human adaptation and survival in increasingly man-made environments during natural disasters is only gradually being appreciated. In recent years emphasis has been placed on man's activities as the major cause of rangeland degradation and famines. It is becoming increasingly clear that drought and famine do not always reflect cause-effect relationships and that the two may coexist independently and often become linked only through politico-economic conditions (Wisner, 1977; Lofchie, 1975; Ball, 1976; Franke and Chasin, 1980: 5; Grossman, 1981; Grove, 1979). In Ethiopia the famine in highland areas in 1972-74 was closely linked to the prerevolution feudal regime (Fitzgerald, 1980; Hussein, 1976; Koehn, 1979; Shepherd, 1975). In the lowlands Bondestam (1974), Cohen (1977) and Flood (1976) associated famine with recent encroachment of pastures by irrigation schemes and with reduced river flooding caused by construction of Koka Dam. However, interaction of physico-environmental and politico-economic factors resulting in the 1972-73 drought and famine and the adaptive responses of the pastoralists in the Awash Valley remain to be studied in depth. The objective of this paper is to examine these relationships among the 130,000 Afar and the 16,000 Kereyu, Arsi and Jile Oromo, the four pastoralist groups traditionally inhabiting the Awash floodplains. The ongoing irrigation development in the Awash Valley with World Bank assistance and the recurrence of drought since 1973 (“Ethiopia”, 1981; Kloos, 1977: 215) make this a timely study. The floodplain ecosystem, although for centuries providing much-needed grazing resources during the dry season, has been relatively neglected in the study of human ecology in Africa (Scudder, 1980: 383). Field work was carried out in 1972/73, 1975/76 and 1982. This was part of disease ecology studies of schistosomiasis and other parasitic infections, irrigation development and migration patterns in the Awash Valley and surrounding highlands (Kloos and Lemma, 1974; Kloos, 1977; Kloos et al., 1981; Kloos, in press) and of a cholera vaccination program in the lower Awash Valley.