Over 90% of the burden of malaria occurs in sub-Saharan Africa. Children, especially under-fives, are the most vulnerable. In Nigeria, Africa's most populous nation, it accounts for 25 and 30% of infant and childhood deaths, respectively. One hundred and seventy-six children who fulfilled clinical and parasitological criteria for the diagnosis of malaria, 26.4% of all under-fives, who presented to the Seventh Day Adventist Hospital in Ile-Ife during the months of May to September 2005 were studied to identify the factors that were associated with severe malaria in the target population. The proportion of children with severe malaria in the study was 17%, while the case-fatality rate was 3.5%. Of the 17 variables examined, high malaria parasite density, non-use of mosquito-bite preventive measures and poverty remained independently and significantly associated with an increased risk for severe malaria. Progress in stemming the burden of malaria depends on accurate knowledge and understanding of the epidemiology and control of the disease in the affected populations.