Declines and persistent low densities of plains ungulates during 1960-1994 in Etosha National Park (Etosha) compromise Namibia's efforts to develop a wildlife- and tourist-based economy and maintain its national biodiversity. Plains ungulates are blue wildebeest (Connochaetes taurinus), plains zebra (Equus burchelli), springbok (Antidorcas marsupialis), and gemsbok (Oryx gazella). We tested the hypothesis that plains ungulate populations were well below their food-resource ceiling (FRC) and predicted that widely variable rainfall (food production) would have no significant effect on birth and survival rates; alternatively, ungulates regulated near their FRC would display strong responses to variable rainfall through negative feedback on fertility, yearling recruitment, and mortality. Data supported the hypothesis that Etosha's populations were well below their FRC. The pregnancy rate of springbok was high during drought. Recruitment of all four species was not positively related to rainfall. Mortality was not negatively related to rainfall, and high mortality did not occur during droughts. Given the high recruitment of Etosha's stable or declining populations, we hypothesize that high adult and yearling mortality resulting from anthrax and predation was the primary process preventing population growth. Management aimed at maintaining or increasing the numbers of Etosha's plains ungulates currently need not emphasize habitat enhancement.