In May 1995, an international team characterized and contained an outbreak of Ebola hemorrhagic fever in Kikwit, Democratic Republic of the Congo. This study reports the descriptive features of this outbreak along with a statistical analysis of the outbreak data. Proportional hazards analysis was used to examine the effect of age, phase of the outbreak, and sex on the risk of death, and a conditional probability analysis was used to examine the effectiveness of whole blood transfusion from convalescent patients on survival. Two hundred fifty case-patients (80.7%) died. The main predictor of survival in the proportional hazards model was age. No statistical evidence of a survival benefit of transfusion of blood from convalescent patients was evident after adjusting for age, sex, and the days since onset of symptoms (P = .1713).